Cytokines and Prostaglandins in Immune Homeostasis and Tissue Destruction in Periodontal Disease

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PeriodonroIogy2000. Vol. 14. 1997,112 143

Printed in Denmark . All rights reservedC o p y r i g h t M u n k s g a a r d 1997

PERIODONTOLOGY 2000ISSN 0906-6713

Cytokines andprostaglandinsin

immune homeostasisandtissuedestructioninperiodontaldisease

E R I CA E MM E L L ,ODERICK. M A R S H A L LGREGORY. S E Y M O U R

Immune homeostasisinperiodontaldisease

Chronic inflammatory periodontal disease manifests

clinically as at least two distinct entities. Evidence

based on microbiological, immunological and ani-

mal model studies has shown that some forms of

periodontal disease in adults can remain stable over

many years and not endanger the life of the den-

tition, whereas other forms, despite extensive treat-

ment, continue to break down, leading ultimately to

tooth loss (279). Periodontal disease is caused by

bacteria in dental plaque, and evidence is increasing

that specific periodontal pathogens are associated

with the progressive form of the disease. However,

some individuals harbor these specific microorgan-

isms but do not appear to show evidence of disease

progression. Patient susceptibility is of utmost im-

portance to the outcome of periodontal disease, and

although periodontal bacteria are the major etiolog-

ical agents, the host immune response to these bac-

teria is of fundamental importance (280).

Susceptibility to periodontal disease is most likely

genetically determined, although a number of local

and environmental factors such as smoking, recent

viral infections and physical and mental stress arethought to influence disease expression (280).Gen-

etic factors divide the population into susceptible

and nonsusceptible people, and individuats may be

in balance with their oral flora as manifested by a

stable lesion and only when the balance is disrupted

by, for example, the appearance of a microorganism

such as Porphjironiotiris girzgiimlis or by depression

of the irnmirne response a s a t.esult of environmental

factors does progression occur. Whether this applies

only to susceptible individuals remains t o be deter-

mined 280).

Periodontal disease results from the interaction of

the host’s defense mechanisms with microorganisms

in plaque, and the immune responses associated

with the pathology of the disease have been the basis

of study for the past 30 years. Histological studies

support the concept that the immune system re-

sponds to plaque microorganisms. The infiltrate in

the periodontal lesion consists of lymphocytes and

macrophages; whereas T lymphocytes predominate

in the stable lesion, the proportion of B cells and

plasma cells is increased in the progressive lesion

(279, 280). Functional assays using peripheral blood

lymphocytes have contributed to the understanding

of the disease process by highlighting a role for T

cells. Most work on immunoregulation of chronic in-

flammatory periodontal disease has therefore fo-

cused on T cells (282). Studies have shown a de-

pressed CD4:CD8 ratio in cells extracted from adult

periodontitis lesions compared with peripheral

blood and healthy tissue or tissue with gingivitis 41,

3031, and T cells extracted from diseased periodontal

tissues have a reduced ability to respond in an auto-

logous mixed lymphocyte reaction (421, suggesting a

suppression of cell-mediated responses. Seymour et

al. (281) demonstrated a lack of interleukin 2 (IL-2)

production by unstimulated T cells extracted from

adult periodontitis patients and suggested this as areason for the failure of these cells to undergo spon-

taneous proliferation (41). In support of this study,

a reduced production of IL-2 andlor IL-2 receptor

expression by T cells in patients with a reduced auto-

logous mixed lymphocyte reaction has recently been

reported (155). Interestingly, the autologous mixed

lymphocyte reaction has been reported to return to

normal following periodontal therapy (296).

Although patient susceptibility is most likely of

major importance in determining the outcome of

periodontal disease, the problems in detecting sus-

ceptible individuals have not been solved. Such func-

112



Cytokines and prostaglandins in periodontal disease

tional studies as proliferation assays or the auto-

logous mixed lymphocyte reaction are not suitable, as

not all individuals with severe disease have a de-

pressed proliferation to periodontal pathogens or a

reduced autologous mixed lymphocyte reaction

(280).There is a great dealof variation in the microbialcomposition between individuals and also from site

to site in the same individual, as well as variation with

respect to the frequency and rate of progression of

periodontal disease (280).A study of cytokines in peri-

odontal disease lesions may throw some light on this

problem and may suggest future lines of therapy.

Immune homeostasis

Cytokines are cell regulators that have a major in-

fluence on the production and activation of different

effector cells. T cells and macrophages are a major

source, although they are produced by a wide range

of cells that play important roles in many physiologi-

cal responses. Cytokines are low-molecular-weightproteins involved in the initiation and effector stages

of immunity and inflammation, in which they regu-

late the amplitude and duration of the response.

They are usually produced transiently, are extremely

potent, generally acting at picomolar concentrations

and interact with specific cell surface receptors,

which are usually expressed in relatively low num-

bers (11). Some cytokines are produced by a re-

stricted type of cell, such as IL-2 produced by T cells,

The type of immune response that occurs on ex-

posure to a pathogen is vital in determining resist-

ance or susceptibility to disease. The importance of

the cytokines induced locally is paramount due to

their different effects on the function of cells in the

immediate neighborhood, which then determines

the course of the response and hence the resistance

or susceptibility to the particular pathogen (28).

Cytokines are recognized as being vital in the im-

munopathology of an ever-increasing number of dis-

eases, and the production of “appropriate”cytokines

is essential for the development of protective im-

munity. If “inappropriate” cytokines are elicited, de-

whereas others, including IL-1 and IL-6, re pro-

duced by very different cell types. Also, target cells

may be restricted or very diverse (123).Many cyto-

kines are pleiotropic, having multiple activities on

different target cells and or overlapping cell regula-

tory actions, but despite this overlap, cytokine func-

tions may not be identical (123). The response of a

cell to a given cytokine depends on the local concen-

tration, the cell type and other cell regulators to

which it is constantly exposed. Cytokines interact in

a network first by inducing each other; second by

transmodulating cell surface receptors: and third by

synergistic, additive or antagonistic interactions on

structive or progressive disease can result (151) (Fig.

1).Just how the immune system selects the right re-

sponse to a particular pathogen is not clear (208).

However, the determination of the features of both

the host and pathogen that direct how and where the

organism is presented to cytokine-producing cells is

necessary in understanding the pathogenesis of all

infectious diseases 151).

cell function 11).

The majority of immune responses occur locally

rather than systemically within a small area of tissue

and often between two cells that are conjugated to

one another (206). Since the discovery of IL-2 in

1976,more than twenty cytokines have been char-

acterized that are essential for many of the prolifer-

ative and differentiative functions of immune cells

206). hus, there appears to be a very complex net-

work of interactions within the immune system.

Mosmann (206) believes that this complexity is es-

sential for overcoming the various defense strategies

of microorganisms.As microorganisms evolve morerapidly than their mammalian hosts, a single im-

mune mechanism could not cope with any new

product synthesized by an infectious agent that in-

terfered with an essential link between cells. Multiple

regulatory mechanisms may therefore be a defense

against pathogen interference and hence could be

essential in the preservation of homeostasis.

Thl and Th2 paradigm

A successful immune response to an infectious agent

depends on activation of appropriate effector func-

Fig. 1. The production of appropriate or inappropriate

cytohes determines aserne expression. Ag: antigen;

A P C antigen-presenting cell

113



Gemmell et al.

tions (243). Extracellular pathogens are generally

eliminated by antibody binding, which facilitates

complement fixation, phagocytosis and activation of

the Fc receptor-dependent release of reactive oxygen

species by monocytes or macrophages and polymor-

phonuclear neutrophils 151). Elimination of intra-cellular pathogens (viruses and certain bacteria), de-

pends on the destruction of the infected cell by anti-

gen-specific cytolytic T cells and activated

macrophages (151). Inactivation of other organisms

occurs by the release of enzyme-rich granules from

eosinophils and mast cells as in the case of hel-

minths, intracellular lysis in the case of infection of

macrophages by bacterial pathogens such as Listeria

monocytogenesor some protozoan parasites such as

Leishmania major, or by sequestration in granu-

lomas as in mycobacterial and schistosorne infec-

tions (151).

Cell-mediated immune responses involve the acti-

vation of macrophages and induction of different

0 4 ' and CD8+ T cells, whereas humoral immunity

is characterized by antibody production. These two

responses were originally classified in the mouse as

being regulated by two distinct subsets of CD4+

helper T cells, termed Thl and Th2 cells, which se-

crete different patterns of cytokines (207). Thl cells

produce 1L-2, interferon (IFN-y) and tumor necrosis

factor p, while Th2 cells are defined by the produc-

tion of IL-4, IL-5, IL-6, IL-10 and IL-13. Both cell

types produce IL-3, tumor necrosis factor a and

granulocyte-macrophage colony-stimulating factor

(152). Human CD4' T cells have cytokine patterns

and functions comparable to those that exist in

mice, although the synthesis of IL-2, IL-6 I L - I 0 and

IL-13 are not as restricted to a single subset as in the

mouse T cell (208). Thl cytokines are involved in

cell-mediated inflammatory reactions. They increase

the ability of macrophages to lull intracellular and

extracellular pathogens and also mediate delayed-

type hypersensitivity reactions (208). Th2 cytokines

are found in association with strong antibody andallergic responses. These cells stimulate mast cells,

eosinophils and immunoglobulin E (IgE) antibodies

and are elevated in allergic diseases and helminth

infections (258). Thl and Th2 cells play different

roles, not only in protection against exogenous anti-

gens, but also in irnmunopathology (258). Therefore

each T-helper subset induces and regulates effector

functions targeted at different antigens and patho-

gens. Although most studies have been on CD4'

cells, it has been reported that the majority of CD8'

T cells have a Thl-like profile. These T cells are cyto-

toxic, and although the pattern of secretion is Thl,

Fig. 2. The balance between suppressorand cytotoxic CD8

T cells may be due to t he level of IL-I0 production

IL-2 secretion is low or undetectable (295). IFN-y is

secreted at about the same level as CD4+ Thl clones,

whereas most other cytokines are secreted at lower

levels. There is evidence that Th2-like CD8+ T cells

also occur in both the human and mouse (20). lnoue

et al. (143) showed that cytolytic CD8+ T cells could

not suppress CD4+ T cells, whereas suppressor

CD8+ T cells could suppress the proliferative re-

sponses of both Thl and Th2 CD4+ cells by the pro-

duction of IL-10 (Fig. 2). IL-4-secreting CD8+ cells

from lepromatous leprosy patients have been shown

to suppress the proliferation of leprosy-specific

CD4+ T-cell clones, and this depended on 1L-4 (269).

Mingari et al. (198) found that their IL-4/IL-5 or

their IL-2-producing CD8+ clones were cytolytic and

that these clones appeared to co-express helper and

cytolytic functions. However, whether CD8+ Type 2

cells provide cognate help for B cells as do CD4+

cells has yet to be reported. What is now evident is

that the pattern of cytokine production by both

CD4' and CD8+ T cells appears to be related to the

function of the cell rather than to the phenotype

(20).

Immune factors that contribute to the manifes-

tations of infectious diseases remain a mystery (202).

Individuals may develop a cellular immune response

resulting in containment or elimination of the infec-

tion. In some susceptible individuals the infection

proceeds unabated due partly to a defect in the

cellular response but not the humoral response,which is usually intact (202). CD4+ T cells play a

major role in protection against parasitic infection

and also in inducing the pathology associated with

the infection (295). The immune response to infec-

tion is regulated by the balance between Thl and

Th2 cytokines. Many recent studies have focused on

the cytokines responsible for immunity or pathology.

The net effect of the Thl cytokines IL-2 and IFN-y is

to enhance cell-mediated responses, whereas that of

the Th2 cytokine IL-4 is to suppress cell-mediated

responses and hence enhance the resistance associ-

ated with humoral immunity (202). However, cyto-

114



Cytokines and prostaglandins in periodontal disease~

Fig.

sors for both Thl and Th2 cells.Ag: antigen

Previous concept in which Tho cells were precur-

kine concentration can also affect the outcome of a

response. Low levels of IFN-y produced by Thl cells

in mice induce antibody with an immunoglobulin

G2a (IgG2a) isotype, but high levels of this cytokine

inhibit B-cell responses. The result of Thl interac-

tion can therefore be help or suppression of anti-

body production. Th2 clones provide help for the

formation of IgM, IgGl (mouse) or IgG4 (human),

IgA and IgE because of the production of the B-cell

proliferation and differentiation factors, IL-4, IL-5

and IL-6 (295). IFN-y, on the other hand, inhibits the

IL-4-induced IgE response (39).In uiuo studies using

cytokines and anti-cytokine antibodies have sup-

ported these observations, providing support for the

concept that the functional abilities of the Thl and

Th2 subsets are due mainly to the cytokines they

produce (295).

The Thl and Th2 model has recently come under

attack as being too simplified. Murine and human T-

cell clone cytokine profiles not fitting this classifi-

cation have been reported (152). Murine IL-2- and

IL-4-producing clones can be derived from the same

cells, suggesting that cytokine phenotype is acquired

during T-cell differentiation and is not secondary to

the expansion of distinct subpopulations predeter-mined to produce a specific cytokine pattern (257).

Most resting T cells secrete IL-2 when first stimu-

lated and then differentiate into cells secreting a

number of cytokines (206). Several secretion pat-

terns seen in short-term in uitro clones that are

clearly not Thl or Th2 may represent early stages

in the differentiation pathway, and the Thl and Th2

cytokine profiles are assumed to represent final

chronically stimulated helper T cells (295). A third

category of T-helper cell clones designated Tho cells

produce a mix of Thl and Th2 cytokines. Until now

it has been believed that, on activation, antigen-spe-

cific naive T cells develop into Tho cells and then

differentiate further into Thl or Th2 cells with re-

peated antigen stimulation (202) (Fig. 3). This pro-

gression through a stage of unrestricted gene ex-

pression is now open to question (152), and Tho cells

may represent other subsets depending on the com-

bination of cytokines. Kelso et al. (153) have shown

that any possible combination of cytokines can be

secreted by individual clones, indicating a random

association between cytokines. Differences in cyto-

kine expression may represent distinct phenotypes,

developmental stages or transient phases in re-

sponse to conditions such as the presence of modi-

fying influences. Mosmann Sad (208) feel, how-

ever, that many T-cell clones and in viuo responses

do show the dichotomy of IL-2 and IFN-y and IL-

4, IL-5 and IL-10 responses and believe it to be an

important dichotomy in the immune response.

Carter Dutton (28) report that there is a natural

tendency towards polarization of T-cell clones and

find it difficult to understand how polarized popula-

tions could be generated if, as suggested by Kelso

(152),an independent regulatory process determines

the secretion of each cytokine.

The balance between local levels of cytokines is

important in determining the outcome of an im-

mune response. The question as to whether acti-

vated T cells can be classified into Thl, Th2 or Tho

subsets wiU not be solved until the presence of as

yet uncloned cytokines that play a role in immunity

has been determined. This classification is con-

venient for now, and what should be kept in mind is

the significance of individual cytokines in the re-

sponse under investigation, and the naming of the

particular T-cell subsets producing them is really a

minor factor. However, many immune responses

seem to involve predominant Thl or Th2 cytokines

(152),and the functional outcome may best be pre-

dicted by the cytokines involved and their respective

antagonists (Fig. 4).

Major cytokines relating to the Thl and Th2paradigm

Interferon gamma. Interferons were first character-

ized as substances that inhibit virus replication, al-

though it is now known that they have many immu-

nomodulatory activities. IFN-y is different in both

biochemistry and biological properties from IFN-a

and IFN-J3 and, whereas the latter are produced by

cells infected with virus, IFN-y is produced during

an immune response by antigen specificT cells and

natural killer cells recruited by IL-2 (225).Its regula-

115





Cvtokines and vrostaalandins in veriodontal disease

Table 1.Summary of major Thl and Th2 cytokine functions

Cytokine Source Functions

Interferon y T cells requisite for induction of Thl cellsnatural killer cells inhibits interleukin 4 activities

enhances interleukin 12 production

stimulates macrophage activity, cytolytic T lymphocytes and natural killer cellsup re da te s class I and 11major histocompatibilitv complex molecules

Interleukin 4 T cells induces Th2 cell differentiationmast cellsbasophils inhibits interleukin 12 production

inhibits interleukin 2- and interferon y-induced activities

induces proliferation and differentiation of B cellsinduces proliferation of T cellsdownregulates monocyte production of interleukin 1, tumor necrosis factor a

and interleukin 6

Interleukin 10 T and B cellsmonocytes and

macrophages

promotes Th2 esponses while suppressingThl cell-mediated responsessuppresses proliferation and cytokhe production by activated T cellssuppresses macrophage function and interleukh 12 productioninhibits macrophage-derived interleukin lu, interleukin 6 and interleukin 8enhances interleukin Ira productionenhances B-cell proliferation and differentiation

~ ~~ ~ ~

Interleukin 12 B cells plays a key role in Thl induction

stimulates growth and cytotoxic activity of natural killer and T cellsprovides a link between natural resistance mediated by phagocytic cells andmonocytes andmacrophagesdendritic cellskeratinocytesLangerhans cellsneutrophils

natural killer cells and adaptive immunity mediated by T-helper cells,cytolytic T lymphocytes and B cells

Interleukin 13 T cells similar functions to interleukin4 although more restricteddownreguIates interleulrin 12 production and, like intedeukin 4

acts as a co-stimulatory signal for human B cells but does not affect T cellsmodulates monocyte and macrophage function including inhibition of

may favor Th2 development

cvtoldne Droduction

towards CD8+ T cells while suppressing the ability

of CD4+ T cells to migrate in response to IL-8 (148).

IL-10 is a potent growth and differentiation factor for

activated human B cells and may therefore play an

important role in amplifying the hurnoral immune

response (264). The synthesis of monocyte-derived

pro-inflammatory cytokines including IL-1-a, IL-6

and IL-8 is inhibited by IL-10, which also enhances

the production of the IL-1 receptor antagonist (IL-

Ira) so that this cytokine dampens immune prolifer-

ation and inflammatory responses (54).

Although both Thl and Th2 cells produce and can

be inhibited by IL-10, it would appear that, in gen-eral, IL-10 promotes Th2 responses while sup-

pressing delayed-type hypersensitivity reactions and

other Thl cell-mediated responses. As a potent anti-

inflammatory reagent, IL-10 is being reviewed in the

light of diminishing the pathology associated with

a number of diseases such as rheumatoid arthritis,

bacterial sepsis and psoriasis (138) (Table 1).

Interleukin 12. IL-12 was originally described as a

factor promoting natural killer and cytolytic T cells

activity. It is produced mainly by monocytes and

macrophages, dendritic cells and polymorpho-

nuclear neutrophils with keratinocytes, Langerhans

cells and B cells producing only low levels (166). L-

12 provides a link between natural resistance med-

iated by phagocytic cells and natural killer cells and

adaptive immunity mediated by T-helper cells, cyto-

lytic T cells and B cells (311). IL-12 has pleiotropic

effects on natural killer cells and T cells. These in-

clude the enhancement of natural killer and T-cell

cytotoxic activity and enhancement of T-cell and

natural killer-cell proliferation after activation by

other stimuli (159,238). IL-12 induces IFN-y produc-

tion by resting and activated T and natural killer cells

(34,159). The early production of 1L-12 representsa key process in natural killer activation and innate

resistance. Natural killer cells can influence the path-

way of Thl and Th2 development when antigen-spe-

cific T cells start to undergo clonal expansion and

differentiation. In this context, natural killer cells

may represent an early source of IFN-)I, which would

contribute to the development of a Thl response.

They appear to be most effective in preventing early

infection, but T and B cells and their products are

required to resolve the infection (12).

Studies have demonstrated that IL-12 plays a key

role in the differentiation of Thl cells. It acts directly

117



Gemmell et al.

on both Thl cells and on their precursors, and part

of this activity is due to the induction of IFN-y pro-

duction by T and natural killer cells. IFN-y has a

positive feedback effect by enhancing the produc-

tion of IL-12 by monocytes and macrophages,

whereas the cytokines IL-4 and IL-10 are powerfulinhibitors of IL-12 production. I t has been suggested

that IL-12 may be the IL-4 equivalent for the differ-

entiation of Thl cells, and these two cytokines may

determine the balance of Thl and Th2 cells (311)

(Table 1). However, this would appear to oversimpl-

ify the situation. It has recently been demonstrated

that IL-12 addition to T-cell cultures during acti-

vation can also result in the promotion of the

2 cytokine IL-4 in addition to IFN-y with or without

IL-10 (166) and to potentiate established Th2 re-

sponses by increasing the proliferation and IL-4 pro-

duction of established Th2-like T-cell clones (147).

These results bring into question the central role of

IL-12 in Thl commitment.

As well as being protective, IL- 12 can also promote

detrimental effects. The administration during ex-

perimental viral infections of doses of IL-12 re-

portedly beneficial in other infections resulted in ad-

verse effects, including inhibition of cytolytic T-cell

activity and virus-induced CD8' T-cell expansion;

the accompanied induction of tumor necrosis factor

was a pivotal factor in the ensuing pathology (230).

Lower doses of IL-12 enhanced CD8+ expansion and

the clearance of virus. This study demonstrated the

potential complications arising from IL- 12 adminis-

tration during an ongoing immune response.

interleukin 13. IL-13 is a potent modulator of hu-

man monocyte and B-cell function. This cytokine is

secreted by both CD4' and CD8+ human T-cell

clones, the CD4+ cells having Tho, Th l and Th2 pro-

files. IL-13 is produced early after activation and over

prolonged periods of time, in contrast to IL-4, which

is secreted much later and occurs transiently (337).

Monocyte cell surface markers including CD23,

major histocompatibility complex class I1 and sev-

eral integrin molecules are upregulated by IL- 13 (55).

The production of the cytokines IL-1 a, IL-1 p, 1L-6,

IL-8 and tumor necrosis factor a induced by lipo-

polysaccharide-stimulated human monocytes is also

inhibited by IL- 13, whereas IL-1 receptor antagonist

secretion is enhanced (55, 337). Therefore IL-13,

along with IL-4 and IL-10, would appear to have po-

tential anti-inflammatory activity (337).Although IL-

13 appears to mimic IL-4, its biological activities are

more restricted than IL-4. t does not, for example,

act o n human or mouse T cells nor on mouse B cells.

although it does act as a co-stimulatory signal for

human B cells (193).

Like IL-4, IL-13 may favor the development of Th2

responses as it downregulates the production of IL-

12. Also like IL-4, IL-13 induces IgG4 and IgE syn-

thesis and directs IgE isotype switching in humans(245). IL-13 and IL-4 genes are closely linked in both

the human and mouse genomes and there is se-

quence homology between the secreted proteins.

The IL-4 and IL-13 receptors also share a common

subunit, although the IL-4 receptor does not bind IL-

13. The production of an IL-4 mutant protein to act

as a receptor antagonist for both IL-4 and IL-13 may

have therapeutic value in the treatment of Th2-pre-

dominant infections (337) (Table 1).

Cytokine regulation

The products of Thl and Th2 cells play a major role

in the regulation, differentiation and subsequent ef-

fector functions of the reciprocal subset (243). Differ-

entiation andlor growth of Thl cells can be inhibited

during a strong Th2 response and vice versa. The

cytokines IFN-y, IL-4, IL-10 IL-12 and IL-13 recipro-

cally regulate the proliferative and cytokine secreting

abilities of T-cell subsets (295). The mechanisms by

which certain T-cell subsets are induced are still

poorly understood (20).I t is possible to bias the type

of immune response to achieve a desired outcome

(20). Several factors are thought to influence the de-

velopment of T-cell subsets, including the antigen it-

self, its concentration and the route of administra-

tion (277). On challenge, priming of mice with inacti-

vated virus or subunit F glycoprotein of respiratory

syncytial virus was shown to induce a Th2-like

lymphocyte response, whereas challenge of mice

primed with live respiratory syncytial virus by par-

enteral or mucosal routes induced a Thl pattern of

cytokine messenger RNA (116). Oral immunization

of mice with sheep red blood cells induced predom-

inantly IL-5-producing Th2-type cells in the Peyer's

patches and spleens, whereas spleen cell cultures of

intraperitoneally immunized mice exhibited a high

proportion of IFN-y-producing cells (328). Oral im-

munization with tetanus toxoid and cholera toxin (a

powerful mucosal immunogen) as adjuvant, selec-

tively induced Th2 cells in mucosa-associated

tissues (329). Adjuvants themselves are able to trig-

ger either CD4' (Thl and Th2) or CD8 T-cell devel-

opment and so modulate selectively the production

of cytokines (10).

The nature of the interaction with the T-cell recep-

tor may also determine cytokine profiles (51). T-cell

118



Cytokines and prostaglandins in p eriodontal disease

receptor-ligand interaction is decisive for the com-

mitment of peripheral blood CD4+T cells toward a

Thl or Th2 response (256). Stimulation of a mouse

CD4 cell clone by three different antigens resulted in

similar levels of proliferation, but only physiological

recognition of major histocompatibility complexclass I1 products plus antigenic peptide or allorecog-

nition of a major histocompatibility complex class I1

alloantigen but not recognition of an Mls-la super-

antigen in association with several major histocom-

patibility complex class I1 products resulted in IFN-y

production (234). Major histocompatibility complex

molecules may also therefore influence the develop-

ment of T-cell subsets. In this context, a single pep-

tide epitope derived from human type IV collagen

has been shown to depend on major histocompat-

ibility complex class I1 expression (277). Thl re-

sponses were observed in H-2s mice, whereas Th2

responses were seen in H-2b mice, suggesting that

quantitative differences in major histocompatibility

complex class I1 binding of antigen may influence

the T-cell response (277).

It is becoming recognized, therefore, that the anti-

gen-presenting cells may influence which T-cell sub-

set is induced. Brain microvessel endothelial cells

and smooth musclelpericytes respectively activate

Th2 and Thl cell clones Preferentially (88). Hepatic

accessory cells support the proliferation of Thl but

not Th2 cells (295). Evidence suggests that B cells

direct CD4+ T cells to a Th2 pathway (20). This is

supported by a study demonstrating the clonal ex-

pansion of ovalbumin-specific Thl and Th2 cells to

be preferentially stimulated by antigen-presenting

adherent cells (macrophagesand dendritic cells) and

antigen-presentingB cells respectively (98). CD5+ B

cells have been suggested as candidates for antigen

presentation to suppressor T cells, indicating that

they may be involved in the induction of a Th2 re-

sponse 20).

Thl and Th2 paradigm inperiodontal disease

A number of studies have reported on the presence

of cytokines in periodontal disease. Pilon et al. (240)

demonstrated lower levels of IL-2 in gingival crevic-

ular fluid of periodontitis sites compared with

healthy sites, and Fujihashi et al. 95) have shown

that gingival mononuclear cells from adult peri-

odontitis patients produce IL-4 and IL-5 but not IL-

2. Significantly less IL-2 activity was found in periph-

eral blood mononuclear cell cultures stimulated by

two putative periodontal pathogens, I gingivalis and

Fusobacteriurn nucleaturn, than in unstimulated cul-

tures (104). In this study, IFN-y as measured by an

immunoassay could not be detected in cultures con-

taining both bacteria and, furthermore, IFN-y wasdemonstrated in only 10/27 gingival mononuclear

cell culture supernatants. Only negligible amounts

were found in 50 of these positive cultures. IL-12

has been found to be significantly reduced in gingi-

val tissue extracted from sites of probing depths

greater than 6 mm compared with tissue from sites

between 3 and 6 mm and normal healthy tissue (83).

These results all suggest decreased Thl responses in

advanced periodontitis.

Memory T cells from the peripheral blood of adult

periodontitis patients with high anti-I?gingiuulis tit-

ers stimulated in uitro with P gingivufis have been

shown to produce higher amounts of IL-4 than do

cells from healthy subjects (4). In this study, no IL-4-

producing memory T cells were detected in healthy

gingival tissues, and a larger proportion of peripheral

blood memory T cells from patients in which high

frequencies of IL-4-producingcells were identified in

the lesion produced IL-4 following stimulation with

antigen. Yamazaki et al. (333) demonstrated an in-

creased percentage of IL-4-positive cells pro-

portional with an increasing ratio of B cells to T cells.

IL-4 was the prominent cytokine in periodontally

affected tissues compared wi th IL-2, IFN-y and IL-6.

The demonstration of concentrations of IgG4 many

times higher in sites of active periodontitis than in

serum as well as significantly elevated concen-

trations compared with stable lesions also suggests

a role for IL-4 and Th2 responses in periodontitis

lesions (252).

A cell dot-blot analysis of cytokine-producing gin-

gival mononuclear cells showed a higher percentage

of unstimulated periodontal disease cells were IL-4

positive and a higher percentage of cells were IL-2

and IL-4 positive when stimulated with €? gingivulis(183). Analysis of IL-2:IL-4 ratios revealed signifi-

cantly lower ratios for cells derived from peri-

odontitis tissues compared with cells from gingivitis

tissues. Taken together, these data seem to support

the hypothesis that Thl cells are associated with the

stable lesion, whereas a Th2 response may lead to

nonprotective antibodies and disease progression.A

Th2 response that results in protective antibodies

may result in elimination of organisms (104, 282). In

contrast, Ebersole Taubman (74) found that the

IFN-)I message was prominently expressed by dis-

eased gingival tissue cells. Cytokine profiles of cells

119



Gemmell et al.

extracted from 6 patients were consistent with Thl

cells in that they were IL-2 and IFN-y positive but

negative for IL-5. A further sample had messages for

IL-2 and IL-5, consistent with Tho cells. This study

speculated that Thl cells may be destructive in peri-

odontal disease via the production of IFN-y and po-tential stimulation of macrophage secretion of IL-1

with subsequent bone resorption. However, the pres-

ence of messenger RNA for IFN-.I, IL-6 and IL-13 but

not for IL-2, IL-4 or IL-5 in CD4+ T cells extracted

from periodontal disease lesions indicates that Tho

cells may be involved in periodontal disease (96).

Takeichi et al. (299) showed that IFN-y and IL-1-p

messenger RNA was expressed by some gingival cells

on extraction, indicating Type 1 cells, and upon

stimulation, IL-6 transcripts were also expressed but

no IL-2 or IL-2 receptor messenger RNA could be

detected. Yet another study on IL-2, IL-4, IL-6, IL-10, IFN-a and I F N - ~ I xpression found no skewing of

cytokines towards a Thl or Th2 profile in diseased

or healthy tissues, although there was a significantly

higher expression of IL-6 and IFN-a messenger RNA

in diseased tissues (244).

T-cell lines and clones specific for I? gingiuulis

have been reported to resemble Tho cells, although

one CD4-positive clone did produce IL-4 and IL-5

messenger RNA, suggesting a Th2 profile (150). An-

other study showed that F gingivalis-reactive T-cell

lines derived from the peripheral blood of a I? gingi-

vulis-infected adult periodontitis and a gingivitis

subject and from the gingival tissues of the adult

periodontitis patient, contained both the Th2 cyto-

kine, IL-4 and the Thl cytokines IFN-)I and IL-2, al-

though there was a higher percentage of IL-4-posi-

tive T cells in the adult periodontitis-derived lines

(102).These data may therefore indicate that the full

range of cytokine-producing T cells (Tho, Thl and

Th2) are all found in both gingivitis and periodontitis

lesions, or may in fact offer supporting evidence for

the concept that such distinction of T cells does not

in reality exist (152). Nevertheless, the Thl ITh2 para-

digm has provided an excellent framework for the

investigation of cytokines in periodontal disease.

Emerging from these studies is the concept that IL-

10 may be of fundamental importance in the control

of periodontal disease progression (Fig. 5). For ex-

ample, only adult periodontitis T-cell lines and de-

rived clones produced IL-10 (102). Stein Hendrix

(294) have also shown a role for IL-10 in periodontal

disease by demonstrating that gingival mononuclear

cells extracted from adult periodontitis patients pro-

duce more IL-10 than cells derived from nonin-

flamed tissue. As well, anti-IL-10 antibodies induced

Fig. 5. The possible role of IL-10 in periodontal disease

homeostasis

an 80970 decrease in the frequency of anti-collagen-

secreting cells, and these authors suggested that IL-

10 in inflamed gingival tissues potentiates a local

autoimmune response characterized by an increase

in the frequency of anti-collagen secreting cells. Arole for IL-10 has also been suggested by another

study that used reverse transcriptase polymerase

chain reaction to analyze cytokine expression in

CD4-positive gingival lymphocytes isolated from in-

flamed periodontal tissues. Two distinct profiles

were noted. One pattern showed the presence of

IFN-y, IL-6, IL-10 and IL-13 messenger RNA; the

other pattern was similar with the exception of a lack

of IL-10 messenger RNA. In most cases, IL-2, IL-4

and IL-5 messenger RNA were not detected (330).

Determination of the correlation of the absence or

presence of IL-10 with the progression of disease

may be worthy of further attention.

Cytokine control of the humoral antibodyresponse

B cells and plasma cells secrete immunoglobulins,

which protect the host by various methods, includ-

ing preventing bacterial adherence, inactivating bac-

terial toxins and by acting as opsonins for phago-

cytosis by polymorphonuclear neutrophils. Poly-

clonal B-cell responses have been cited as being

important in the pathogenesis of the progressive

periodontal lesion (306) and it is generally agreed

that polyclonally induced immunoglobulin produc-

tion in humans is regulated by T cells (27,2621.How-

ever, the question of whether antibodies produced

in response to periodontal pathogens are protective

or not is still controversial.

B cells produce IL-1, which acts as a co-stimu-

latory signal for Th2 cells as well as mediating tissue

destruction via a number of pathways (233). If the

result of B-cell differentiation was protective anti-

body production, elimination of the causative organ-

120




ism would ensue and disease progression would

stop. There is recent evidence to suggest that peri-

odontopathic organisms may not be part of the nor-

mal flora (106), hence, elimination of these organ-

isms would not only limit progression of the disease

(237) but may be a desirable outcome of the immuneresponse. Production of nonprotective antibodies in

susceptible subjects could, on the other hand, result

in continual connective tissue breakdown. Periods of

destruction would precede periods of stability and

the disease may have a cyclical pattern, with not all

B-cell lesions being destructive (104, 282).

The majority of T cells in the gingival tissues are

memory or primed cells (101,332),and a number of

studies have suggested the presence of peri-

odontopathic antigen-specific T and B cells in the

gingival tissues. Limit dilution analysis has demon-

strated the presence of T cells specific for I gingi-

valis and Actinomyces viscosus (the predominant or-

ganism found in the plaque of gingivitis subjects) in

the peripheral blood of gingivitis and periodontitis

patients (180). nitial treatment and the reduction in

plaque and hence antigen load resulted in a reduc-

tion in the frequency of I gingivulis- but not A.

viscosus-specific T cells in the adult periodontitis

subjects, although treatment resulted in a reduction

in both in gingivitis subjects. T-cell lines responsive

to I? gingivulis and E nucleutum have been shown to

be major histocompatibility complex class I1 re-

stricted and exhibit helper activity for B cells, as de-

termined by their ability to induce high levels of IgG

production in the presence of antigen (145).

Although direct evidence for the involvement of

antigen-specific T cells in chronic inflammatory

periodontal disease in humans has still not been

demonstrated, use of an animal model has shown

that cells of an Actinobacillus actinomycetemcomit-

uns-specific T-cell clone A3 adoptively transferred

into normal Rowett rats resulted in increased IgG

and IgM serum antibodies to A. actinomycetem-

comituns and reduced periodontal bone loss after in-fection (331).Athymic recipients showed no signifi-

cant antibody production or protection from bone

loss. When A3 clone T cells were adoptively trans-

ferred together with naive lymph node T cells from

normal rats into A . actinomycetemcomituns-infected

athymic animals, there was a significant increase in

specific serum antibody levels as well as in vitro pro-

liferation of spleen lymphocytes to antigen com-

pared with nude animals receiving lymph node T

cells alone (72). These authors suggested the lymph

node T cells have enabled survival of the A3 cells in

the athymic mice. These studies have demonstrated

that specific antibody can be protective in peri-

odontal disease, further supporting the concept of

local antigen-specific immune responses.

Protection has been demonstrated in a number of

studies. Serum from patients with severe peri-

odontitis containing high titers of anti-I? gingivulisantibodies completely inhibited in vitro bone re-

sorption, whereas serum from patients with low tit-

ers failed to inhibit this bone resorption, indicating a

possible protective role for specific antibodies (194).

Immunization of a 43-kDa fimbrial protein provided

protection against periodontal tissue destruction

when tested in I gingivulis-infected gnotobiotic rats

(871, and Kesavalu et al. (154) demonstrated that in

animals immunized w i t h I? gingivalis, the resulting

antibodies elicited gave a measure of protection by

functioning primarily as opsonins resulting in

phagocytic destruction of virulence components.

Complement-mediated killing of I gingivulis by hu-

man serum also appeared to depend on the pres-

ence of high levels of specific antibody in sera from

periodontally healthy patients, and those with adult

periodontitis containing low levels had little bacteri-

cidal activity (228).

However, not all anti-I? gingivulis antibodies are

protective (321). Schenk (272) reported significantly

greater levels of IgG and IgA antibody against I gin-

givulis lipopolysaccharide in periodontitis subjects

than controls with a healthy periodontium, and Ke-

savalu et al. (154) found that immunization with

whole cells or lipopolysaccharide of P gingivalis pro-

vided no protection against the lethal effects after

challenge with lipopolysaccharide. Chen et al. (36)

also demonstrated that immunization of mice with I

gingivulis lipopolysaccharide did not result in readily

detectable IgG or IgM levels to lipopolysaccharide,

nor did it reduce the severity of P gingivulis infec-

tion. Taken together, these results suggest that re-

sponses to lipopolysaccharide do not induce a pro-

tective response and that a response to these anti-

gens may not prevent progression of disease.Lipopolysaccharideand other carbohydrate antigens

tend to stimulate IgG2 rather than IgGl or IgG3,

which are generally produced in response to protein

antigens (226, 273). A predominance of serum IgG2

antibodies that lack strong complement fixation and

opsonic properties have been reported in peri-

odontal disease subjects, so that the humoral re-

sponse to I? gingivufis may be ineffective in clearing

this organism (176, 321). A nonprotective immune

response is also suggested by studies demonstrating

the presence of low-avidity anti-I? gingivalis anti-

bodies, which may be incapable of effectively medi-

121



Gemrnell et al.

Fig. 6.Tumor necrosis factor a (TNF-a) and IL-1 mediate

adhesion molecule expression on endothelid cells and

hence play a role in the migration of polymorphonuclear

neutrophils (PMNs), lymphocytes and macrophages MQ)into the periodontal tissues

ating a variety of immune responses (176, 3211, and

the general inability to demonstrate immune com-

plexes in the gingival sulcus (37, 105, 2411, support-

ing the notion that there is a compromised ability to

eliminate or reduce the numbers of microorganisms

and their products from the gingival sulcus (176).

Macrophages and dendritic cells both bind anti-

gen by relatively nonspecific mechanisms. The exist-

ence of different antigen-presenting cells raises the

question about differences in their roles in the acti-

vation of T cells. Macrophages and dendritic cells

may provide signals that initially activate T cells,

while B-cell presentation then allows for further acti-

vation and clonal expansion of these already acti-

vated cells. Evidence that B cells direct Th2 CD4+

T cells whereas macrophages activate Thl cells (20)

provides support for antigen-specific T- and B-cell

activation leading to Th2 responses in the B-cell

periodontitis lesion. It is of interest that the A3 cells

used in the above studies were Th2 cells, and

Eastcott et al. (72) have suggested that Th2 cells are

protective in periodontal disease and Thl cells are

destructive. Ebersole Taubman (74) speculate that

Th2 cells produce IL-4 and IL-5, which are essential

for B-cell production of antibody. Even though the

Th2 A3 antigen-specific cells induced protective

antibody, the cytokine profiles of antigen-specific T

cells in the periodontal lesion in humans and their

relationship to protective and nonprotective anti-

bodies have yet to be determined.

Cytokines in tissue destruction

IL-1 is a principal mediator of inflammatory re-

sponses acting on many cell types and is itself pro-

duced by many different cells, including macro-

phages, endothelial cells, B cells, fibroblasts, epi-

thelial cells, astrocytes and osteoblasts in response

to microorganisms, bacterial toxins, complement

components or tissue injury (60). One of the most

important actions of IL-1 is its induction of othercytokines (224), and it appears to be part of a net-

work of cytokines with self-regulating and self-sup-

pressing properties (108). IL-6 is produced by both

hemopoietic and nonhemopoietic cells and induces

immunoglobulin secretion in both preactivated mu-

rine and human B cells and therefore induces the

final maturation of B cells into high-rate immuno-

globulin-secreting cells (224). Like IL-1, it appears to

have a major role in the mediation of inflammatory

and immune responses initiated by infection or in-

jury. Tumor necrosis factor is also a multipotential

cytokine having a wide variety of biological effects

and has been suggested to have similar effects as IL-

1 (170). Tumor necrosis factor a is produced mainly

by macrophages in response to agents such as lipo-

polysaccharide (38). Both tumor necrosis factor a

and IL-1 have been shown to act on endothelial cells

to increase the attachment of polymorphonuclear

neutrophils and monocytes and thus help to recruit

these cells into sites of inflammation (16) (Fig. 61.

IL-1 and tumor necrosis factor a are key mediators

of chronic inflammatory diseases and have the poten-

tial to initiate tissue destruction and bone loss in peri-

odontal disease (18). L-1 has been shown to stimulate

fibroblasts in culture to produce collagenase (253).

Tumor necrosis factor also mediates tissue destruc-

tion by stimulating collagenase (50) and degradation

of type 1collagen by fibroblasts leading to connective

tissue destruction (196). IL-1 is the most potent

known inducer of bone demineralization (Fig. 7) and

synergizes with tumor necrosis factor a n stimulating

bone resorption (292) as well as major changes in the

connective tissue matrix (246). On its own, tumor ne-

crosis factor is one hundred fold less potent than IL-1

Fig. 7. 1L-1produced by macrophages ( M 0 ) as the major

mediator of tissue breakdown in periodontal disease

122



Cvtokines and mostanlandins in periodontal disease

in bone resorption assays (292). Tumor necrosis factor

molecules stimulate bone resorption by inducing the

proliferation and differentiation of osteoclast pro-

genitors and activating formed osteoclasts indirectly

(15,210,307).L-6 lso appears to have a role in bone

resorption. This cytokine was first found to stimulate

the formation of multinucleated cells with features

similar to osteoclasts (195) nd has now been shown

to be a potent stimulator of osteoclast differentiation

and bone resorption (259) and inhibitor of bone for-

mation (141).

Destructive cytokines in periodontal disease

IL- levels have been shown to be elevated in the gin-

giva of adult periodontitis subjects compared with

clinically healthy or gingivitis-affected individuals

(136, 08) and from active periodontitis sites versus

inflamed stable sites (293). urthermore, IL-1 evels

decrease after periodontal treatment (188, 91). IL-6

has also been shown to be increased in the gingival

crevicular fluid of patients with refractory peri-

odontitis (251),and IL-6message has been detected

in inflamed gingival tissues but not al l healthy tissues

examined (298). n the latter study,IL-6 rotein could

only be demonstrated in the inflamed tissues. Neither

of these studies correlated bone or connective tissue

destruction directly with IL-6evels.

As well as demonstrating the presence of IL-1-j3n

all gingival crevicular fluid samples collected fromsevere periodontal breakdown, tumor necrosis factor

a was also detected although in only about half the

samples and at only about 10% of the concentration

of IL-1-p 335).Another study also showed tumor ne-

crosis factor a o be present at very low or undetect-

able levels in gingival crevicular fluid (2631, nd Mat-

suki et al. (190)demonstrated that tumor necrosis

factor was produced by macrophages in inflamed

gingiva. Activated macrophages are also a well estab-

lished source of IL-1-p roducing up to ten times

more IL-1-pmessenger RNA than IL-1-a essengerRNA (59, 184). Matsuki et al. (191) howed defini-

tively using combined immunohistochemistry and

in situ hybridization that the IL-1messenger RNA-

expressing cells in human inflamed gingiva were

macrophages. The rate of IL-1messenger RNA was

higher in the connective tissue furthest from the

pocket epithelium, suggesting a role in the alveolar

bone resorption that occurs in periodontal disease.

This is supported by a study demonstrating that ad-

ministration of IL-1-p ccelerated alveolar bone de-

struction in ligature-induced periodontal tissue in-

flammation in rats over a 2-week period (162).

Human gingival fibroblasts may also contribute

significant levels of certain inflammatory cytokines

in the gingival tissues (67).Formalin-killed prepara-

tions of two possible periodontal pathogens, A. acti-

nornyceterncomitans and Carnpylobacter rectus have

been shown to stimulate IL-6 nd IL-8productionby human gingival fibroblasts although IL-1-pwas

suppressed during the initial 3- o 12-hour period.

Reddi et al. (250) also showed that surface-associ-

ated material ( S A M ) rom a number of oral patho-

gens including A. actinornycetemcornitans Eikenella

corrodens, I gingivalis, C . rectusand Prevotella inter-

media induced IL-6 ut not IL-1-f3 r tumor necrosis

factor a from gingival fibroblasts, although all three

cytokines were induced from peripheral blood

mononuclear cells. A. actinornyceterncomitans E.

corrodens and I gingivalis were the most potent in-

ducers, especially A. actinornyceterncomitans which

has also been shown to have bone-resorbing activity

(325).Gingival fibroblasts may therefore be able to

contribute to periodontal tissue inflammation (67).

Hendley et al. (134) uggested that oral polymor-

phonuclear neutrophils may be an important source

of IL-1-p n periodontal disease, as the amount pro-

duced by these cells was strikingly greater than that

produced by circulating polymorphonuclear neutro-

phils activated in vitro. Keratinocytes which have

been demonstrated to produce IL-1-a 164), ould

also be a source of IL-1 n the gingival tissues, al-

though Matsuki et al. (191)could not detect IL-1

messenger RNA or protein in the epithelium of peri-

odontal disease subjects.

Whether B cells contribute to IL-1 n inflamed gin-

gival tissues has not yet been demonstrated. How-

ever, Ito et al. (146)have shown that lipopolysac-

charide from I gingivalis, I? intermedia and A. acti-

nornyceterncomitans increased the numbers of

osteoclast-like cells in lipopolysaccharide-respon-

sive C3HIHeN bone marrow cells in culture. They

concluded that lipopolysaccharide from gram-nega-

tive bacteria in periodontal pockets may induce os-teoclastic differentiation and promote alveolar bone

loss in periodontal disease. The method of action of

this increased osteoclast differentiation and any in-

volvement of cytokines produced by lipopolysac-

charide-induced polyclonal B-cell activation were

not determined.

Inhibitors of destructive cytokines

The IL-lra is a member of the IL-1gene family that

binds IL-1 eceptors without inducing apparent cell

activation. It is produced by monocytes 6)and poly-

123



Gemmell et al.

morphonuclear neutrophils (249), and an intracellu-

lar variant is produced by keratinocytes (17). Tumor

necrosis factor a has been reported to induce both

intracellular IL-lra and IL-1-a by keratinocytes, and

the ratio of these two cytokines may influence the

inflammatory profile in the epidermis (165). It is un-

clear whether the IL-lra actually acts as an antagon-

ist in uivo as high levels of IL-lra have been reported

(215) at sites of chronic inflammation such as the

synovium of patients with rheumatoid arthritis.

However, increasing mucosal inflammation in in-

flammatory bowel disease in children has been

shown to be associated with a decrease in the effec-

tive IL-1ra:IL-1-f3 atio in which IL-lra normally pre-

dominates (142). Dinarello (61) has also reported

that, due to the ability of IL-lra to block IL-1 recep-

tors without agonist activities, the severity of several

diseases such as septic shock, inflammatory bowel

disease and experimental arthritis has been reduced.

In support of this, Norman et al. (218) showed that

tumor necrosis factor a and IL-6 are elevated and

correlate well with the severity of local pancreatic

destruction during experimental acute pancreatitis

in mice. Administration of IL-lra before or after the

induction of pancreatitis significantly attenuated the

rise of these cytokines and was associated with de-

creased severity of pancreatitis and reduced intrinsic

pancreatic damage. The use of IL-lra has also been

shown to delay the onset and reduce the severity of

paralysis and shorten the duration of disease in anexperimental allergic encephalitis, an animal model

of multiple sclerosis (1871, and treatment of rabbits

with experimentally induced acute colitis with IL-lra

markedly reduced the severity of inflammation and

necrosis of the colon (45). High levels of IL-lra have

also been measured in the gingival crevicular fluid

of patients with adult periodontitis (140) although

the relevance to disease has not been determined.

Furthermore, P388D1 murine macrophages have

been shown to produce an IL-1 inhibitor identical to

the IL-lra after stimulation with A. acrinomycerern-cornitans lipopolysaccharide, which may play an im-

portant mediatory role in the development of peri-

odontal disease (217).

Soluble cytokine receptors reduce the biological

effects of cytokines by decreasing the concentration

of surface receptors and by binding free cytokine

and consequently reducing the concentration of sol-

uble cytokine and therefore the biological effects of

cytokines (140). There are two IL-1 receptors, type 1

and 11. While type receptors signal, type I1 can bind

IL-1 but will not transduce a signal. w e 1 receptors

arc cleaved and shed and in the plasma will bind IL-

~ ~ ~~~ ~

1-p but not IL-lra (297). Therefore there is no com-

petition between the soluble receptor and the recep-

tor antagonist (140). Tumor necrosis factor a L-1

and lipopolysaccharide have been shown to induce

soluble tumor necrosis factor a receptors by mono-

cytes (135). Increased soluble tumor necrosis factor

a eceptors have been found in the sera and synovial

fluids of patients with rheumatoid arthritis (46), and

high levels of both the p55 and p75 tumor necrosis

factor a receptors have been demonstrated in gingi-

val crevicular fluid from periodontal disease sites

(140).

Several cytokines have been implicated in the sup-

pression of tissue destructive cytokines. IL-10 has

been shown to downregulate IL-I and tumor ne-

crosis factor a gene expression in human monocytes

(86) and polymorphonuclear neutrophils (30, 31).

Further, IL-10-deficient mice suffer from chronic en-

terocolitis similar to human inflammatory bowel dis-

ease, which is characterized by the infiltration of

neutrophils and mononuclear cells (242) and is as-

sociated with increased tissue levels of tumor ne-

crosis factor, IL-1, IL-6 and IL-8 (62). IL-10 has been

demonstrated to down-regulate IL-1-f3 and tumor

necrosis factor a secretion as well as messenger RNA

levels in peripheral monocytes and mononuclear

cells from the lamina propria of patients with in-

flammatory bowel disease. At the same time, IL-lra

secretion was induced and IL-10 was able to restore

diminished in uitro IL-1ra:IL-1-P ratios to normal

levels. In uivo topical application of IL-10 to patients

with ulcerative colitis resulted in the down-regula-

tion of proinflammatory cytokine secretion both loc-

ally and systemically (274).

IL-4, like IL-10, has been shown to downregulate

IL-1 and tumor necrosis factor a gene expression in

human monocytes (86) and to inhibit their secretion

and that of another proinflammatory cytokine, IL-6

(305). Furthermore, IL-4 has been shown to induce

the death by apoptosis of IL-1- or Iipopolysacchar-

ide-stimulated monocytes, but not unstimulatedmonocytes (182). Human monocytes contribute to

both the persistence and resolution of chronic in-

flammation, and the regulation of the production of

monocyte mediators may have great value in healing

or in reducing the immunopathogenesis of chronic

inflammation (181).

Transforming growth factor p is an anti-inflam-

matory agent (239). It is produced locally at the site

of resorption of bone and has been shown to initiate

new bone formation (32). Transforming growth fac-

tor p appears to be an IL-1 inhibitor and acts by re-

ducing the constitutive or induced level of IL-1 re-

124




ceptors (70). Gemmell Seymour (103) demon-

strated that more transforming growth factor p may

have been produced by peripheral blood mono-

nuclear cells in culture in the absence of stimulatory

bacteria, confirming another study which showed

that without specific bacterial stimulation, the pre-dominant product by peripheral blood adherent

cells was inhibitory (319). Furthermore, Winning et

al. (326) demonstrated the absence of a factor of ap-

proximately the same molecular weight as the IL-lra

in supernatants of periodontal diseased epithelial

cells, which was consistently found in healthy epi-

thelial cell supernatants. Hammerberg et al. (124)

have suggested the presence of an IL-lra isolated

from sections of skin by polymerase chain reaction

analysis could possibly have been derived from Lan-

gerhans cells. Howells (140) states that destructive

periodontal disease may be due to insufficient levels

of inhibitors rather than increased levels of IL-1 and

tumor necrosis factor a.The mechanisms of interac-

tions of cytokines in periodontal disease need to be

elucidated to be able to use cytokine inhibitors clin-

ically to the best advantage.

IL-8 is produced by a wide variety of cell types

including polymorphonuclear neutrophils, mono-

cytes and macrophages, fibroblasts and keratino-

cytes in response to microorganisms, mitogens and

endogenous mediators such as IL-1 and tumor ne-

crosis factor. IL-8 has been implicated as a major

participant in a number of diseases, including rheu-

matoid arthritis in which increased levels correlated

with increased polymorphonuclear neutrophils

numbers in collected synovial fluid samples (161).

Studies have shown that lipopolysaccharide-stimu-

lated polymorphonuclear neutrophils release IL-8 as

well as IL-1-p and tumor necrosis factor a,which

both independently can induce IL-8 secretion them-

selves (29). lipopolysaccharide-stimulated polymor-

phonuclear neutrophils also secrete IL-lra, which re-

sults in the blocking of IL-8 synthesis in monocytes

(117) and IL-8 release in polymorphonuclear neutro-phils (29). One of the major functions of IL-8 is its

ability to induce the directional migration of cells,

including polymorphonuclear neutrophils, mono-

cytes and T cells (229), thus playing a key role in the

accumulation of leukocytes at sites of inflammation

(215).As the primary effector cells in acute inflam-

mation, human polymorphonuclear neutrophils

synthesize and release inflammatory cytokines and

thereby modulate both T- and B-cell function (174).

Production of IL-8 by polymorphonuclear neutro-

phils suggests that having arrived at the site of in-

flammation, these cells promote the further recruit-

ment of polymorphonuclear neutrophils and the ac-

cumulation and activation of monocytes and

macrophages and lymphocytes (29).

Polymorphonuclear neutrophils are terminally

differentiated short-lived cells so that their ability to

produce cytokines may be regarded as havinglimited physiological significance (29). However,

polymorphonuclear neutrophils survival can be ex-

tended by exposure to signals such as lipopolysac-

charide and the cytokinesIL-1-p, tumor necrosis fac-

tor a, L-6, IFN-y and certain colony-stimulating fac-

tors 24, 44). Polymorphonuclear neutrophils are

found not only within the sulcular and junctional

epithelium and within the underlying connective

tissue (9, 2751, but also comprise over 90 of the

leukocytes in gingival fluid (8). IL-8 has been de-

tected in the gingival crevicular fluid of adult peri-

odontitis patients (2351, and cytokine message has

been identified in both healthy and diseased peri-

odontal tissues (309). Furthermore, IL-8 message has

been shown to be restricted to the junctional and

sulcular epithelium in close proximity to infecting

organisms, and this was consistent with the localiz-

ation of polymorphonuclear neutrophils in the same

area, suggesting a role for IL-8 in the selective re-

cruitment of polymorphonuclear neutrophils to-

wards the infecting plaque bacteria (310).

Both protective and destructive influences of

polymorphonuclear neutrophils have been sug-

gested such that their role in adult periodontal dis-

ease is still controversial. Much of the evidence

suggesting a protective function comes from the ob-

servation that patients with systemic polymorpho-

nuclear neutrophils defects such as neutropenia, ag-

ranulocytosis and Chkdiak-Higashi syndrome also

display an increased severity in periodontal break-

down (313). However, bacteria and bacterial prod-

ucts are capable of evading polymorphonuclear neu-

trophils using a number of mechanisms. Some peri-

odontal bacteria such as I gingivalis, A.

actinomycetemcomitans and E nucleaturn have beenshown to inhibit some of the protective functions of

polymorphonuclear neutrophils such as phago-

cytosis, chemotaxis, production of superoxide dis-

mutase and direct leukocytotoxicity (2,288). MacFar-

lane et al. (179) reported significantly impaired

phagocytosis due to a decreased rate of adhesion

and opsonization by polymorphonuclear neutro-

phils from patients with refractory periodontitis

compared with healthy patients, suggesting a strong

association between polymorphonuclear neutrophil

defects and refractory disease. Bacteria, including I

gingivalis, produce proteases that can cleave com-

125



Gemmell et al.

plement and immunoglobulins preventing opsoniz-

ation and subsequent polymorphonuclear neutro-

phi1 killing of invading bacteria (314).Yamazaki et al.

(334) have shown that peripheral blood polymor-

phonuclear neutrophils stimulated with a range of

periodontopathic bacteria did not produce IL- 1 butrather an IL-1 inhibitor. In contrast, a nonoral micro-

organism did induce IL- 1 secretion. The results sug-

gested a mechanism whereby periodontopathic bac-

teria could evade the protective effects of polymor-

phonuclear neutrophils and also indicated a

regulatory role for these cells in periodontal disease.

Prostaglandins and prostaglandin inhibitors

Cytokines exert their effect by first binding with spe-

cific receptors that, in turn, bind to second messages

so that a signal is delivered inside the cell in re-

sponse to the cytokine ligand (47). One group of sec-

ond messengers is derived from hydrolysis of mem-

brane phospholipids. Phospholipase A, cleaves its

substrate to generate arachidonic acid, a precursor

of a group of small lipids known collectively as eicos-

anoids, which act as inflammatory agents (173).Ara-

chidonic acid is degraded via one of two pathways.

The action of lipoxygenases (a group of additional

oxidative enzymes) results in the formation of the

hydroxyeicosatetraenoic acids and leukotrienes. Al-

ternatively, prostaglandin endoperoxide synthases

(cyclooxygenase) catalyze the conversion of arachi-

donic acid into the prostanoids (prostaglandins and

prostacyclins) and thromboxanes (128).

Prostaglandins are comprised of 10 classes, of

which D, E, E G, H and I are the most important

biologically (128). The existence of the prosta-

glandins has been known for many years, but their

role in inflammation was only revealed in the 1960s

(139). Evidence that prostaglandins could mediate

bone resorption was first reported in 1970 (156, 247)

and a role for prostaglandins in periodontal bone

loss soon followed (111, 112).Early work established

prostaglandin E, as the most potent stimulator of

bone resorption (58, 115),and subsequent studies in

periodontal disease have tended to concentrate on

this particular prostaglandin (76, 219). Prostaglandin

E, exhibits a broad range of proinflammatory effects.

It contributes to the flare and weal effects by in-

ducing vasodilation and increasing capillary per-

meability, and these effects are enhanced by syner-

gism with other inflammatory mediators (323). IL-1

and tumor necrosis factor activate the arachidonic

acid pathway, and a number of their effects can be

attributed to prostaglandin E2 (38).

Increased production of the eicosanoids is associ-

ated with inflammatory reactions (38)and one treat-

ment of inflammation has been directed towards the

enzymes which release these products. Cyclooxygen-

ase (COX) was isolated in 1976 (2001, but its wide

distribution fails to explain the differing prostanoidproductions seen across differing tissues. Recently, a

second form of cyclooxygenase (now designated

COX-2) was isolated (163, 287). COX-2 expression is

inducible in response to a number of stimuli includ-

ing lipopolysaccharide (172, 232) and many cyto-

kines such as IL-1, tumor necrosis factor and trans-

forming growth factor a (71, 107, 149). While both

COX-1 and COX-2 catalyze the same reaction, at

resting conditions COX-2 is mostly undetectable

(278). Recently, a third isoform (COX-31, possibly in

the brain, has been speculated (315). With the dis-

covery of COX-2, there has been a renewed interest

in the development of drugs to block the action of

cyclooxygenase.

Corticosteroids have long been used to control in-

flammation. The specific action of the cortico-

steroids on phospholipase A2 has recently been de-

duced. The action appears to be indirect, causing the

release of lipocortin, an inhibitory protein, from

some cells (318).Alternatively, cytoplasmic glucocor-

ticoid receptors may also be activated. These recep-

tors regulate transcription of some primary response

genes, including those responsible for COX-2 (94).

This same receptor complex is also responsible for

inhibiting transcription of some cytokines including

IL-1 and tumor necrosis factor a (13). The conven-

tional anti-inflammatory drugs have been retrospec-

tively examined to determine their COX-1 and -2 sel-

ectivity and these, along with more recent drugs, are

shown in Table 2.

As inflammatory cytokines have the ability to up-

regulate COX-2, inhibition of these cytokines may

represent another area of COX-2 control. Radicicol is

a fungal antibiotic thought to act as a protein tyro-

sine kinase inhibitor and has been shown to inhibit

the expression of COX-2 in lipopolysaccharide-

stimulated macrophages without effecting enzy-

matic activity (35). A new family of drugs, the cyto-

kine-suppressing anti-inflammatory drugs, has been

described (1 91, of which SKF 86002 is the prototype

(2361,These drugs are potent and selective inhibitors

of one of the mitogen-activated protein kinase fam-

ily termed alternatively RK, p38 or cytokine-sup-

pressing anti-inflammatory drugs-binding protein.

These protein kinases are thought to act as signal

transducers when activated by physicochemical

stress, lipopolysaccharide or pro-inflammatory cyto-

126



Cvtokines and m ostanlandins in veriodontal disease

Table 2. Selective inhibition of cyclooxygenase

by nonsteroidal anti-inflammatory drugs

DIUE cox-1 cox-2

Aspirin (167)Indornethacin (163)

Piroxicam (167)Naproxen (167)Tenidap* I2311

Ibuprofen (167)

Nabumetone (289)

Etodolac (167)Nimesulide (R-805) 14)

Hosulide (CGP 8238) (157)

Meloxicam (65.841

NS-398 (109)

L-745,337 (23, 33)

sc 58125 (35, i44)T-614b I35,302)

I

BF-389 (199)

Also nhibits monocyte interleukin l p production (37, 100).

Also inhibits monocyte interleukin 18 and interleukin 6 production (49,301).

kines such as IL-1 and tumor necrosis factor (171).

Activation is required for production of IL-1 and tu-

mor necrosis factor and probably prostaglandins, as

cytokine-suppressing anti-inflammatory drugs have

been shown to inhibit strongly the production of

COX-2 in response to IL-1 (120).

The use and complete understanding of COX-2 in-

hibitors is still in its infancy, however it seems likely

that in the future, various drugs either blocking the

enzyme or inhibiting its production will come to be

used as important modulators of inflammation.

Prostaglandins in periodontal disease

In vitro studies of the effect of prostaglandins on

periodontal tissues have concentrated on two ap-

proaches: studies of the production and effects of

prostaglandins per se and studies of the effect of

drugs to inhibit Prostaglandins. Early studies showed

the possibilities for bone resorption from gingival

fragments, and indomethacin was used to elucidatea role for prostaglandins (111, 112, 114).The produc-

tion of prostaglandins from gingival tissue increases

with inflammation and is further increased by estro-

gens and progesterones (75). Human monocytes

have also been shown to produce prostaglandin E2

when stimulated with lipopolysaccharide from puta-

tive periodontal pathogens (99). lnflamed gingival

samples synthesize significantly larger amounts of

prostaglandins when incubated with arachidonic

acid than do healthy gingival samples (197). Al-

though most work has concentrated on prosta-

glandins, homogenates of inflamed gingiva metab-

olize most arachidonic acid via the lipoxygenase

rather than the cyclooxygenase pathway (77).Within

gingival lesions, prostaglandin E is mainly localized

within macrophage-like cells, suggesting a possible

immune regulatory role (175).

Resting monocytes from localized juvenile peri-odontitis patients have been shown to secrete sig-

nificantly more prostaglandin E2 than those from

control patients or severe generalized periodontitis

patients. Stimulation with lipopolysaccharide caused

a dose-dependent increase in prostaglandin E2 pro-

duction, which was significantly greater than that

shown by severe generalized periodontitis patients,

which was, in turn, significantly greater than that

found in controls (283). Recent work by the same

group indicated that the lipopolysaccharide hyper-

sensitivity of localized juvenile periodontitis mono-

cytes can be reversed depending on the age of the

cell cultures, highlighting some of the risks of in v i m

studies (284).

Both gingival and periodontal ligament fibroblasts

secrete prostaglandin E in response to IL-1-p and

also in response to media conditioned by lipopoly-

saccharide-stimulated monocytes (253). More recent

work has shown that periodontal ligament cells pro-

duce prostaglandin E even when unstimulated, but

this secretion is enhanced by incubation with IL-1,

IL -1 -B and tumor necrosis factora, nd the addition

of parathyroid hormone further enhances this effect

(267, 268). Incubation with combinations of these

cytokines and IFN-7 may have additive, synergistic,

subtractive, or suppressive effects on prostaglandin

E production by periodontal ligament fibroblasts

(266).

Cultivated gingival mononuclear cells from

chronic adult periodontitis patients produce elev-

ated IgG levels, which can be decreased by the ad-

dition of indomethacin. Prostaglandin E2 has a bi-

phasic action on these cells, whereby high doses de-

crease IgG levels but low doses increase them. When

combined with IL-4, ow doses of prostaglandin E2induce a synergistic rise in IgG production, sug-

gesting an immunoregulatory role for prostaglandin

E2 (127). Differing putative periodontal pathogens

appear to have differing activating abilities, and al-

though A. actinomycetemcomitans and Wolinella

recta both stimulate gingival fibroblasts to produce

IL-6 and IL-8, only W recta at high concentrations

causes an increase in prostaglandin E2 levels (67).

Various nonsteroidal anti-inflammatory drugs

have been used to further our understanding of the

role of prostaglandins and the possible effectiveness

of drugs in treating gingival inflammation (78). Of-

127



Gemm ell et al.

fenbacher et al. (221) have developed an in uifro as-

say for testing the prostaglandin E2 production from

periodontal tissue homogenates and have been able

to test a range of nonsteroidal anti-inflammatory

drugs for their inhibitory effects. Similarly, rat bone

marrow stromal cell cultures have been used as abioassay for periodontal ligament fibroblast osteo-

genic inhibitory factors. All prostaglandins were

found to be inhibitory, although prostaglandin E,

and prostaglandin Fza were the most potent (227).

Gingival fibroblasts treated with prostaglandin E2

showed a significant concentration dependent inhi-

bition of D N A synthesis and could also reduce the

stimulation of DNA synthesis by IL-1-p and indo-

methacin (79). Both IL-1-p and tumor necrosis factor

a stimulated IL-6 production from gingival fibro-

blasts, but endogenous and exogenous prosta-

glandin E2 down-regulated this production at the

post-transcriptional level (300).

Conversely, triclosan (a nonionic antibacterial

compound) has been shown to inhibit the produc-

tion of prostaglandin E2 from IL- I-p-stimulated gin-

gival fibroblasts, possibly by inhibiting cyclooxygen-

ase (with a COX-1 preference) (97). It has been

shown that IL- 1 - p increases messenger RNA levels

for COX-2 but not COX-1 in gingival fibroblasts, and

this upregulation is prevented by dexamethasone

(an anti-inflammatory steroid) (336). Most prosta-

glandins have been shown to have an overall cata-

bolic effect on gingival fibroblasts, as evidenced by

their ability to alter cell morphology, suppress pro-

liferation and suppress DNA synthesis, collagen syn-

thesis and noncollagenous protein synthesis, al-

though there is no apparent effect on GAG synthesis

5).CyclosporineA, a common immunosuppressant

associated with gingival overgrowth, has a dose-de-

pendenr inhibitory effect on prostaglandin I, syn-

thesis in gingival tissues. As prostaglandin I nor-

mally exerts an anti-proliferative effect, i t has been

suggested that the lack of prostaglandin I? is respon-

sible for the gingival overgrowth associated with

cyclosporine A 214).

Animal studies. A hamster periodontitis model has

been used to show the inhibitory effects of indo-

methacin on bone resorption, suggesting that

prostaglandins may be in viuo uncouplers of bone

remodeling (265).Similar results with indomethacin

have been obtained in a squirrel monkey model and

even more inhibition of bone resorption was noted

with a topically applied nonsteroidal prostaglandin

synthetase inhibitor (316). Infusion of prostaglandin

E, over 3 weeks has been shown to have a dramatic

local osteogenic effect in dogs, although the long-

term stability of this new bone is unknown (185).

The dynamics of prostaglandin E2 production

have been followed in ligature-induced periodontitis

in rhesus monkeys. A 3-fold increase in the crevic-

ular fluid levels of prostaglandin E2 occurred after 3months, a 6 fold peak was found at 6 months with a

return to baseline levels after 12 months. The rise in

prostaglandin E2 levels correlated positively with the

clinical signs, which also plateaued at 6 months

(220). A similar rise was seen in beagles with nat-

urally occurring periodontal disease, and this in-

crease was significantly reduced by systemic ibup-

rofen, naproxen and topical flurbiprofen, further

emphasizing the role of the cyclooxygenase pathway

in periodontal bone loss (223) .In Wistar rats, the ap-

plication of prostaglandin E2 to the gingival sulcus

resulted in a dose-dependent increase in the number

of osteoclasts, although concentrations greater than

1.0 mglml were less effective (201).

By contrast, exogenous prostaglandin El adminis-

tered systemically to hamsters resulted in a marked

decrease in the number of osteoclasts, although their

intrinsic activity was enhanced and bone formation

was totally inhibited (26).In addition, near-by deliv-

ery of prostaglandin El in beagle mandibles has been

reported to result in the formation of cementum, al-

veolar bone and Periodontal ligament in 18 of 18 ex-

perimental sites compared with 1 of 7 control sites

(186).

Clinical studies. Assays for prostaglandins have

been performed on gingival tissues removed at

surgery. Prostaglandin E2 and thromboxane A2 were

detected only in inflamed tissues and while 6-K-

prostaglandin F1 was found in all tissues, lower

levels were detected in uninflamed gingivae (57).

Longitudinal monitoring of mean full-mouth crevic-

ular fluid prostaglandin E2 levels predicts well peri-

odontal attachment loss in the following 6 months.

Thus, as a screening test, the prostaglandin E2 levels

have a high degree of sensitivity (0.761, specificity

(0.96) and predictive value (0.92-0.95) at the patient

level but not necessarily at the site (222).

A double-blind clinical trial of the effects of

flurbiprofen on bone loss in a 6 month pre-treat-

ment period compared with the subsequent 2 years

(322) showed that the rate of bone loss in patients

talung the drug was significantly less than those re-

ceiving a placebo, although after 24 months there

was no difference between the bone loss rates of the

two groups. The authors speculated that the late loss

of this clinical effect could be due to a true loss re-

128




lated to a switching to other bone resorptive path-

ways or simply to a decrease in patient compliance

after such a long period. The use of flurbiprofen has

also been assessed in resolving pre-existing gingival

inflammation. Systemic flurbiprofen alone reduced

significantly the Gingival Index scores and gingivalcrevicular fluid flow rates despite having no effect

on the amount of plaque, although there was little

additional benefit to be gained over toothbrushing

solely or in combination with the drug (132).

The experimental gingivitis model has also been

used to follow the changes in crevicular fluid prost-

anoid and cytokine levels in developing gingivitis.

Both IL-1-p and leukotriene B4 levels increased

rapidly but prostaglandin E2 and thromboxane B4

levels only increased in the fourth week, correspond-

ing to an increase in bleeding scores (130).This same

group used the model to examine the effect of

flurbiprofen on the prevention and treatment of gin-

givitis. The drug significantly inhibited the develop-

ment of redness and bleeding in the first 21 days

which were associated with a significant inhibition

of gingival crevicular fluid thromboxane B2 but not

prostaglandin E2.Over the following 7 days (21-28

days) the flurbiprofen continued to inhibit bleeding

but not redness, and this was associated with inhi-

bition of the significant rise in crevicular fluid

prostaglandin E2, hromboxane B2 and leukotriene

B4 seen in placebo control patients (131). A follow-

up study using systemic flurbiprofen (100 mglday)

with toothbrushing to resolve gingivitis showed no

difference in plaque and crevicular fluid flow after 7

days but greater resolution of inflammation in the

experimental group. Whether this difference was sig-

nificant clinically remains to be seen (133).A further

use of topical flurbiprofen (as a 1 w/w toothpaste)

has been tested over 12 months in patients treated

for chronic periodontal disease. Although there was

no significant difference between the treatment and

control groups in terms of clinical response, there

was a significantly greater proportion of sites show-ing bone gain (8%) compared with the placebo

group (3.3%) 129).

The association of prostaglandins with increasing

inflammation has proved difficult to characterize.

While increasing levels are seen from health to gingi-

vitis to periodontitis (2121, healthy sites in patients

with periodontitis experience also have higher levels

of prostaglandin E, although levels are lower in

maintenance patients than in patients with ongoing

periodontitis. Thus individual site levels of prosta-

glandins are difficult to reconcile with the clinical

appearance of the site in isolation (73).

Cytokine therapy

As mentioned earlier, many diseases are due to inap-

propriate cytokine activity; hence, the use of cyto-

kines to change the course of the disease or to allevi-

ate symptoms or side effects of other therapies is be-coming important in clinical medicine (38).

Cytokines can theoretically be used as therapeutic

modalities in two forms. As already mentioned, over-

production of cytokines may be inhibited by the

cytokine-suppressing anti-inflammatory drugs. Al-

ternatively, missing, defective or reduced cytokines

andlor their receptors can be replaced directly to re-

constitute a reduced immune system or used to

stimulate further the immune system in cases of

overwhelming infection or neoplasias. These therap-

ies can be achieved using recombinant cytokines or

genes encoding for them.

Cytokine therapy is initially very attractive; how-

ever, a number of clinical problems have arisen that

complicate the reality. The initial attraction for cyto-

kine therapy was in hematopoiesis. Following cyto-

toxic chemotherapy, bone marrow transplants and in

conditions such as aplastic anemia, neutrophil dys-

functions and agranulocytosis, there is a need for

rapid growth of normal cells (203). Early work with

pancytopenic monkeys (66) and patients recovering

from autologous bone marrow transplant (216)

showed that injection of recombinant human granul-

ocyte-macrophage colony-stimulating factor resulted

in a rapid increase in neutrophils. This increase was

dose-dependent, and could be maintained for up to a

month without significant side effects as long as the

infusion continued. Cessation of therapy resulted in

the return to normal cell levels in 3-7 days.

In the treatment of tumors, early work began with

the recognition that incubation of leukocytes with

IL-2 resulted in a cytotoxic cell capable of killing tu-

mor cells (118). Clinical trials of this technique in

humans using ex uivo incubated leukocytesw i th co-

administration of IL-2 resulted in significant tumorregression but were also associated with systemic

fluid retention due to leaky capillaries. This effect

was probably due to induction of other cytokines

and limits the dose that can be administered. Renal

cell carcinoma and melanoma appear to be most

susceptible to this form of therapy (261). Systemic

IFN-a nd locally administered tumor necrosis fac-

tor have also been used successfully in clinical trials.

In the future it may be ideal to combine cytokines to

increase their therapeutic effects, as has been done

with IL-3 and granulocyte-macrophage colony-

stimulating factor.

129



Gemmell et al.

In infectious diseases, IFN-y and IL-2 can be used

to some effect in the treatment of lepromatous lep-

rosy (213) and cutaneous leishmaniasis (921, due

most likely to an alteration in the ThllTh2 balance

(270).This fine balance has been studied in a murine

model of Schistosoma infection in which excessiveamounts of IL- 10 suppress IFN-7 production. Treat-

ment with anti-IL-10 antibodies in this model may

represent a correction in the balance of the anti-Thl

activities of IL-10 and the anti-Th2 effects of IFN-y

(285). Conversely, IL-10 may be useful in the treat-

ment of Thl-mediated diseases such as contact der-

matitis and possibly psoriasis 7).

Recombinant cytokines and or their inhibitors can

be used in the control of rheumatoid arthritis. A

number of short term clinical trials have been

undertaken using a variety of cytokine-blocking

mechanisms. Tumor necrosis factora, n importantmediator in arthritis, can be blocked by the use of

cA2, a chimeric (human/mouse) neutralizing anti-

tumor necrosis factor monoclonal antibody (158).

double-blind study of cA2 indicated a significant im-

provement as measured by a number of parameters

of disease (81) nd this effect continued even with

repeated administration (82). Other positive results

have been reported with CDP571 (a humanlmouse

anti-tumor necrosis factor a monoclonal antibody)

(248) and a sTNFR:Fc fusion protein (twosoluble tu-

mor necrosis factor receptor molecules fused to the

Fc portion of human IgG1) (204). The use of a re-

combinant human IL-1 receptor has also been tried

for the treatment of rheumatoid arthritis. Early re-

sults were promising but later trials have noted sig-

nificant side effects and questionable benefit (69).

Other positive results have been reported with an

anti-IL-6 monoclonal antibody (B-E8) (320).

In different clinical situations, cytokines, combi-

nations of cytokines, antibodies to cytokines, soluble

receptors for cytokines and agonists could all be po-

tentially used for treatment. Two major problems re-

main to be overcome. One is the need to achieve the

cytokine levels or blockade in the long term, and the

second is to overcome the adverse outcomes that

may result from systemically blocking or increasing

cytokines that are normally involved in homeostasis

(80).Any cytokine treatment for periodontal disease

probably needs to address these problems.

Gene therapy

Over the last decade, advances in the understanding

of the molecular basis of diseases have led to a much

Fig. 8. Principles of gene therapy. Ag: antigen.

greater understanding of disease processes, which in

turn has led to the concept of gene therapy. The pri-mary aim of gene therapy is to treat disease states

through gene insertion strategies to correct genetic

defects in somatic cells (126). It can be viewed as

using DNA as a drug, either to correct a defect, en-

hance a response or mark a foreign cell for sub-

sequent eradication. Gene modification can occur ex

uiuo or in uivo and can involve either normal or ab-

normal cells. Problems have arisen for long-term

changes, as there is a need to alter early precurser

cells and often these cells are not dividing, or in-

serted genes may not remain transcriptionally active.

The procedure of altering the genornic contents of

the cell requires the use of a vector to carry and in-

sert the new genetic material (Fig. 8). Methods that

have received approval to date include retroviruses,

adenoviruses, liposomes and direct DNA injection.

Retroviruses can only incorporate smaller genes

(maximum 7 kb) due to their relatively small genome

(19).These viruses contain single-stranded RNA, and

once in the host cell, the viral RNA must undergo

reverse transcription to double-stranded DNA which

is then incorporated into the host cell genome. This

property of most retroviruses means that integration

only occurs in dividing cells. Because most tissues in

adults consist of nondividing cells, these vectors are

usually applied ex uiuo and in humans have been

used to transfect autologous T cells (3) and bone

marrow cells (137) with the adenosine deaminase

gene, which is deficient in severe combined im-

munodeficiency disease and liver cells with the low-

density lipoprotein receptor gene (121). Adeno-

viruses usually result in mild diseases in humans

but, in contrast to retroviruses, these contain double

stranded DNA and do not require host cell division

for replication. The viral genome is much larger

130



Cytokines and prostagland ins in periodontal disease~ ~~

(about 35 kb) and more complex than that of retro-

viruses. Adenovirus vectors have been used in

humans in the treatment of cystic fibrosis 48);how-

ever, because adenoviruses do not integrate into di-

viding cells, their therapeutic effect may be transi-

ent, requiring repeated administration, but this maybe limited by the immunogenic effects of the wild-

type adenoviruses. Adeno-associated viruses contain

single linear strands of DNA and require simul-

taneous infection of the host cell with adenovirus or

certain other viruses in order to replicate. The main

problem for use as a vector appears to be that the

introduced DNA cannot be very big (less than 5 kb)

and currently is difficult to produce in large quan-

tities.

Viral vectors have been modified such that they

cannot produce systemic infections but retain the

ability to be incorporated into the cell. For the gene

insertion therapy to work, 1) the gene must be in-

serted into a large number of cells; 2) the new gene

must be persistently active;3) the gene product must

be compatible with the biology of the target cell to

cause the therapeutic effect (particularly with re-

spect to humoral and cellular immunity);and 4) The

vector titers need to be high enough to increase the

chances of the new DNA being incorporated into the

rare target cell that is dividing (in the case of retro-

viruses).

Some cationic and neutral lipids (liposomes) com-

plex with DNA to form structures that can transfect

DNA into cultured cells. The transfection is generally

not as efficient as that associated with viruses, and

expression is generally only transient. Nevertheless,

it is attractive because it avoids any theoretical con-

cerns of using viruses. Vaccines are currently under-

going trial using prostate-specific antigen and 17-1A

(a colorectal associated antigen) in liposome vectors

(189). DNA/polylysine complexes appear to be taken

up by some cells by receptor-mediated endocytosis.

Possible useful receptors include the transferrin re-

ceptor (317)and the polymeric IgA receptor (89).Ad-dition of an adenovirus helps to disrupt the endo-

some to release the vectored DNA (49). Naked DNA

is taken up by cells in some tissues (327).The uptake

is not very efficient but the effect can be long lasting.

It may be of use in vaccine applications, as both a

humoral and cellular immunity may develop. Naked

DNA has also been used in balloon angioplasty to

get transient expression of endothelial cell growth

factor (255).

Linkage of genes to form chimeric receptors has

also been proposed. Linkage of the signal transduc-

tion domain of IL-2 with the extracellular domain

of a growth-stimulating factor such as granulocyte-

macrophage colony-stimulating factor may provide

a means of promoting in vivo expansion of T cells

that are sensitized to specific viruses such as cyto-

megalovirus (254). A similar approach has been

taken with the herpes thymidine kinase and hygro-mycin genes (1781, and in an ex uiuo use of the same

technique, allografted T cells contained the same

combination to allow ganciclovir to be used to con-

trol graft-versus-host disease (192).

Cancer therapy trials are the most prominent area

of gene therapy research (189). It has been noticed

that tumor cells do not express or have low ex-

pression of major histocompatibility complex class I

or B7 antigens, resulting in poor or no antigen pres-

entation and thus preventing T-cell activation. Tu-

mor cells have been infected with viruses containing

the cDNA for these antigens and IL-2, and when re-

turned to the body can lead to systemic T-cell re-

sponses. This effect has been successful in animals

and is currently being used in human trials for the

treatment of melanoma, lung cancer, a range of solid

tumors (209) and renal cell carcinoma (271).

An alternative approach is the use of viruses with

recombinant tumor antigen genes. This has been

successful in forming tumor rejection immunity in

mice, but because most human tumor-associated

antigens are variations of normally expressed anti-

gens, they are likely to be only weakly immunogenic,

although this may be overcome by the addition of

further antigens to enrich the response. An alterna-

tive is to give the tumor additional anti-genes so they

can be recognized by cytolytic T cells. To this end,

the gene for HLA-B7 has been transfected into mela-

noma cells resulting in the tumors expressing HLA-

B7 (211)with subsequent regression of some lesions.

As mentioned above, another approach has been

the incorporation of the herpes thymidine kinase

gene into tumor cells, usually by direct injection of

viral particles into the tumor. The herpes thymidine

kinase then sensitizes the cells to ganciclovir, whichcan then be used to treat the tumor. There appears

to be an intracellular transfer of the phosphorylated

ganciclovir, which leads to many more tumor cells

being sensitized, this phenomenon being known as

the bystander effect (93). A similar approach has

been tried with cytidine deaminase and 5-fluorocy-

tosine (122). 'Ikials are currently under way using

gene sensitization for the treatment of glioblastom-

as, melanoma, mesothelioma and ovarian cancer.

A further application of gene therapy in cancer

treatment has been the concept of chemoprotec-

tion. Use of chemotherapy in the treatment of can-

131



Gemmell et al

cer is often limited by the toxicity of the drugs on

normal cells. Bone marrow cells can be transfected

with MDR-1 (multi-drug resistance) gene ex vivo

such that when reintroduced, the patient can re-

ceive greater doses of chemotherapy without

threatening the marrow (125). The retrovirally in-duced cDNA is incorporated into relatively few

hematopoietic cells but each successive generation

will further propagate the resistance, allowing in-

creasing chemotherapy dosages (160). In a similar

vein, radiotherapy and chemotherapy sensitivity of

tumors has been attributed to the presence of

both damaged DNA and a functional p53 tumor

suppressor protein. The introduction of wild-type

p53 gene into resistant tumors has shown promis-

ing results by introducing sensitivity in animal

models (3241, and preliminary results in the treat-

ment of lung, liver and colorectal cancer have

been very encouraging 22, 168).

It may also be possible to treat cancer with genet-

ically modified tumor vaccines. Animal studies have

shown that ex uivo manipulation of tumor cells can

generate an immune response that is effective

against the original tumor when returned to the sub-

ject, but whether this will be effective in humans re-

mains to be seen (110). Difficulties in extrapolating

the technique to humans include obtaining suf-

ficient tumor tissue for vaccine preparation and the

use of a suitable vector for modifying the tumor cells

to make them more immunogenic.

Cytokine gene therapy

The use of genes encoding for cytokines or their an-

tagonists for the treatment of a number of disease is

also being tested. Viruses encoding the IL-lra have

been used effectively in animal models of arthritis

and also to prevent the re-occlusion of vessels fol-

lowing balloon angioplasty for atherosclerotic

plaques.

Cytokines can be used in a number of ways toachieve anti-tumor immunity. As mentioned above,

genes encoding for tumor-specific antigens and

cytokmes can be used in viral vectors or just the

cytokine gene itself can be transfected into the tu-

mor cell ex uivo or in vim The cross-regulation of

Thl and Th2 responses by IFN-y, IL-4 and 1L-10

have led to the study of cytokines for use in shift-

ing the balance towards a cell-mediated Thl re-

sponse. IL-10 is known to downregulate the ex-

pression of B7 and major histocompatibility com-

plex antigens (64), which have low expression on

tumor cells. Transfection of tumor cells with vari-

ous cytokines (tumor necrosis factor, IL-2, IFN-y,

IL-4 and granulocyte-macrophage colony-stimulat-

ing factor) have all been shown to lead to tumor

rejection in mice, and in some cases elimination

or reduced growth of the tumor (169). There is

currently no consensus as to which cytokine andwhich vector is the most useful clinically in terms

of actual useful treatment as opposed to just look-

ing at the immune response (43).

Despite some very promising results, it should be

remembered that gene therapy is still very much in

its infancy, and while many applications seem poss-

ible there are often many pitfalls in achieving a clin-

ically significant result. Such difficulties are high-

lighted by the trials to achieve factor VIII expression

in retrovirally transfected fibroblasts, muscle cells

and endothelial cells (126).

Conclusion

Understanding of the pathogenesis of periodontal

disease has made enormous progress over the past

5 years, but this progress has recognized higher level

complexities hitherto unknown. The concept of Th l

and Th2 cells based on their cytokine profiles led to

the development of hypotheses for the pathogenesis

of periodontal disease that highlight the concept of

susceptibility and nonsusceptibility for the first time.

These hypotheses have provided a framework for the

study of cytokines in periodontal disease that has

produced somewhat conflicting results. Variation in

results reported by different laboratories, however,

cannot always be explained by the techniques used,

and patient selection probably has a major role. The

conflicting results in many of these studies make it

clear that accurate criteria for assessment of disease

activity and for patient susceptibjlity are required to

allow meaningful interpretation of data. Prediction

of clinical disease activity in patients is not yet poss-ible, and only the measurement of past activity is

currently available. The establishment of a means for

classifylng patients as susceptible or nonsusceptible

and sites as stable or progressive is therefore necess-

ary to define patient selection more precisely. If this

is achieved, it may then be possible to test the Thl/

Th2 hypothesis (74, 282) and to determine the role

of IL-10, other cytokines, cytokine inhibitors and

prostaglandins, in controlling disease progression.

Only then will it be possible to design specific cyto-

kine or gene therapies for the treatment of peri-

odontal disease.

132



References

1.Allison JP. CD27-B7 interactions in T-cell activation. curr

Opin Imrnunol 1994: 6 414-419.

2. Angelini SM, TrevinoAC, Novak MJ. Mechanisms of neu-

trophil immobilization by membrane vesicles of Porphyr-ornonus gingivufis. Dent Res 1994: 73: 347 (abstr 1961).

3. Anderson W Human gene therapy. Science 1992: 256:

808-813.

4. Aoyagi T, Sugawara-Aoyagi M, Yamazaki K Ham K In-

terleukin 4 (IL-4) and IL-6-producing memory T-cells in

peripheral blood and gingival tissues in periodontitis pa-

tients with high serum antibody titers to Porphyrornonas

gingivulk Oral Microbiol Immunol 1995 1 0 304-310.

5. Arai H, Nomura Y Kinoshita M, Shimizu H, Ono K, Goto

H, Takigawa M, Nishimura F, Washio N, Kurihara H, Mu-

rayama Y. Response of human gingival fibroblasts to

prostaglandins.1Periodont Res 1995 3 0 303-311.

6. ArendW nterleukin 1 receptor antagonist.A new mem-

ber of the interleukin 1 family. J Clin Invest 1991: 88:1445-1451.

7. Asnis L, GaspariA. Cutaneous reactions to recombinant

cytokine therapy. J Am Acad Dermatoll995: 33 393-410.

8. Attstrom R, Egelberg J. Emigration of blood neutrophils

and monocytes into the gingival crevice. J Periodont Res

1970:5: 48-55.

9. Attstrom R. Studies on neutrophil polymorphonuclear

leukocytes at the dento-gingival junction in gingival

health and disease. J Periodont Res 1971: 8(suppl): 1-15.

10. Audibert FM, Lise LD. Adjuvants: current status, clinical

perspectives and future prospects. Immunol Today 1993:

11. Balkwill FR, Burke E The cytokine network. Immunol To-

day 1989: 9: 299-304.12. Bancroft GJ. The role of natural killer cells in innate resist-

ance to infection. Cum Opin Immunol 1993:5: 503-510.

13. Barnes PI, Adcock I. Anti-inflammatory actions of ster-

oids: molecular mechanisms. Trends Pharmacol Sci 1993:

14: 436-441.

14. Barnett J, Chow J, Ives D, Chiou M, Mackenzie R, Osen E,

Nguyen B, Tsing S, Bach C, Freire J, Chan H, Sigal E,Ra-

mesha C. Purification, characterization and selective inhi-

bition of human prostaglandin GIH synthase 1 and 2 ex-

pressed in the baculovirus system. Biochim Biophys Acta

1994: 1209: 130-139.

15. Bertolini DR, Nedwin GE, Bringman JS, Smith DD, Mundy

GR. Stimulation of bone resorption and inhibition of for-

mation in vitro by human tumor necrosis factors. Nature1986: 319: 516-518.

16. Bevilacqua MI: Pober JS, Wheeler ME, Cotran RS, Gim-

brone MA Jr. Interleukin 1 acts on cultured human vascu-

lar endothelium to increase the adhesion of polymorpho-

nuclear leukocytes, monocytes, and related leukocyte cell

lines. J Clin Invest 1985: 76: 2003-2011.

17. Bigler CF, Noms DA, Weston WL, Arend WP. nterleukin-1

receptor antagonist production by human keratinocytes. J

Invest Derrnatol 1992: 9 8 3844.

18. Birkedal-Hansen H. Roles of cytokines and inflammatory

mediators in tissue destruction. J Periodont Res 1993 28

500-510.

19. Blau H, Springer M. Gene therapy a novel form of drug

delivery. N Engl J Med 1995: 333: 1204-1207.

14: 281-284.

20. Bloom BR, Salgame P, Diamond B. Revisiting and revising

suppressor T cells. Immunol Today 1992: 13: 131-136.

21. Bohjanen PR, Okajima M, Hodes RJ. Differential regula-

tion of interleukin4 and interleukin 5 gene expression: a

comparison of T-cell gene induction by anti-CD3 anti-

body or by exogenous Iymphokines. Proc Natl Acad Sci U

S A 1990 87: 5283-5287.22. Bookstein R, Demers W, regory R, Manevol D, Park J

Wills K. p53 gene therapy in vim of hepatocellular and

liver metastatic colorectal cancer. Semin Oncol 1996:23:

23. Boyce S, Chan CC, Gordon R, Li CS, RodgerW Webb JK,

Rupniak NM, Hill RG. L-745,337: a selective inhibitor of

cyclooxygenase-2 elicits antinociception but not gastric

ulceration in rats. Neuropharmacol 1994:33: 1609-161 1.

24. Brach MA, DeVos S, Gruss HJ, Herrmann E Prolongation

of survival of human polymorphonuclear neutrophils by

granulocyte-macrophage colony-stimulating factor is

caused by inhibition of programmed cell death. Blood

1992 80: 2920-2924.

25. Brown M, Hu-Li J Paul WE. IL-4IB cell stimulatory factor1 stimulates T cell growth by an IL-2-independent mech-

anism. J Immunol 1988: '131: 504-511.

26. Caillon P Saffar J. Improvement of gingival and alveolar

bone status in periodontitis-affected hamsters treated

with 15-methyl prostaglandin El , J Periodont Res 1994:

29: 13845.

27. CarpenterAB, Sully EC, Ranney RR, Bick PH. T-cell regula-

tion of polyclonal B-cell activation induced by extracts of

oral bacteria associated with periodontal diseases. Infect

Immun 1984: 43: 326-336.

28. Carter LL, Dutton RW 'Qpe 1 and 'Qpe 2: a fundamental

dichotomy for all T-cell subsets. Curr Opin Immunoll996:

8: 336-342.

29. CassatellaMA, GasperiniS, Calzetti F, McDonald PI: a i n -chieri G. Lipopolysaccharide-inducednterleukin-8 gene

expression in human granulocytes: transcriptional inhi-

bition by interferon-gamma. Biochem J 1995: 310: 751-

755.

30. Cassatella MA, Meda L, Bonora S, Ceska M, Constantin G.

Interleukin 10 (IL-10) inhibits the release of proinflam-

matory cytokines from polymorphonuclear leukocytes.

Evidence for an autocrine role of tumor necrosis factor

and IL-1 beta in mediating the production of IL-8 trig-

gered by lipopolysaccharide. J Ekp Med 1993: 178: 2207-

2211.

31. Cassatella MA, Meda L, GasperiniS, Calzetti F, Bonora S.

Interleukin 10 (IL-10) upregulates IL-1 receptor antagon-

ist production from lipopolysaccharide-stimulated hu-man polymorphonuclear leukocytes by delaying mRNA

degradation. J Exp Med 1994: 179: 1695-1699.

32. Centrella M, McCarthy TL, Canalis E. Skeletal tissue and

transforminggrowth factor p. FASEB J 1988: 2: 3066-3073.

33. Chan C, Boyce S, Brideau C, Ford Hutchinson AW Gordon

R, Guay D, Hill RG, Li CS, Mancini J, Penneton M, Prasit

P, Rasori R, Riendeau D, Roy D, Tagari I: Vickers P, Wong

E, Rodger I. Pharmacology of a selective cyclooxygenase-

2 inhibitor, L-745,337: a novel nonsteroidal anti-inflam-

matory agent with an ulcerogenic sparing effect in rat and

nonhuman primate stomach. J PharmacolExp Ther 1995:

34. Chan SH, Perussia B, Gupta yWKobayashi M, Pospisil M,

Young HA, Wolf SE Young D, Clark SC, Trinchieri G. In-

101-107.

274 1531-1537.

133



Gemmell et al.

duction of interferon gamma production by natural killer

cell stimulatory factor: characterization of the responder

cells and synergy with other inducers. J Exp Med 1991:

173: 869-879.

35. Chanmugam P, Feng L, Liou S, Jang BC, Boudreau M, Yu

G, Lee JH, Kwon HI, Beppu T, Yoshida M, Xia Y,Wilson C,

Hwang D. Radicicol, a protein tyrosine kinase inhibitor,suppresses the expression of mitogen-inducible cyclooxy-

genase in macrophages stimulated with lipopolysacchar-

ide and in experimental glomerulonephntis. J Biol Chern

1995: 270: 5418-5426.

36. Chen PB, Davern LB, chifferle R, Zambon IJ . Protective

immunization against experimental Bacteroides (Porphyr-

omonus) gingiualis infection. Infect Immun 1990: 58:

3394-3400.

37. Clagett ]A, Page RC. Insoluble im mun e complexes and

chronic periodontal diseases in man and the dog. Arch

Oral Biol 1978: 23: 153-165.

38. Clemens MJ. In: Read Ap: Brown T, ed. Cytokines. Oxford:

Bios Scientific Publishers, 1991.

39. Coffman RL, Carty I. A T cell activity that enhances poly-clonal IgE production and its inhibition by interferon-

gamma. J Immunol 1986: 136: 949-954.

40. Coffman RL,Ohara J Bond Mw arty 1 Zlotnik A, Paul

WE. B cell stimulatory factor-I enhances the IgE response

of lipopolysaccharide-activated cells. J Immunol 1986:

136: 4538-4541.

41. Cole KC, Seymour GJ, Powell RN. The autologous mixed

lymphocyte reactions (AMLR) using periodontal lympho-

cytes. 1 Dent Res 1986: 65: 473, abstract no. 16.

42. Cole KC, Seymour GJ, Powell RN. Phenotypic and func-

tional analysis of T cells extracted f rom chronically in-

flamed human periodontal tissues. J Periodontol1987: 58:

43. Colombo M, Rodolfo M. Tumor cells engineered to pro-duce cytokines or cofactors as cellular vaccines: do ani-

mal studies really support clinical trials. Cancer Immunol

Immunother 1995: 41: 265-270.

44. Colotta F Re E Polentarutti N, Sozzani S, Mantovani A.

Modulation of granulocyte survival and programmed cell

death by cytokines and bacterial products. Blood 1992:

80: 012-2020.

45. Cominelli E Nast CC, Clark BD, Schindler R Lierena R

Eysselein VE, hompson RC, Dinarello CA. Interleukin 1

(IL-1) gene expression, synthesis, and effect of specific IL-

1 receptor blockade in rabbit immune complex colitis. J

Clin Invest 1990: 86: 972-980.

46. Cope AE Aderka D, Doherty M, Engelmann H, Gibbons

D, Jones AC, Brennan FM, Maini RN, Wallach D, Feld-mann M. Increased levels of soluble tumor necrosis

factors in the sera and synovial fluid of patients with

rheumatic diseases. Arthritis Rheum 1 992 35: 1160-

1169.

47. Cosman D, Lyman SD, Idzerda RL. Beckmann MI? Park

LS,Goodwin RG, March CJ. A new cytokine receptor su-

perfamily. Trends Biochern Sci 1990: 15: 265-270.

48. Crystal R, McElvaney N, Rosenfeld M, hu C-S, Mastrang-

eli A, Hay JG, Brody SL, Jaffe HA, Eissa NT, Dane1 C. Ad-

ministration of an adenovirus containing the human

CFTR cDNA to the respiratory tract of individuals with

cystic fibrosis. Nature Genet 1994: 8: 42-47.

49. Curie1 D, Wagner E, Cotten M, Birnstiel M, garwal S. ti

CM, Loechel S H u PC. High efficiency gene transfer med-

569-573.

iated by adenovirus coupled to DNA-polylysine complex-

es. Hum Gene Ther 1992: 3: 147-154.

50. Dayer JM, Beutler B, Cerami A. Cachectinltumor necrosis

factor stimulates collagenase and prostaglandin E2 pro-

duction by hum an synovial cells and dermal fibroblasts. J

Exp Med 1985: 162: 2163-2168.

51. De Maeyer E, De Maeyer-Guignard J. Interferon-y. CurrOpin Immunol 1992 4 321-326.

52. Del Prete G, De Carli M , Almerigogna E Giudizi MG, Bi-

agiotti R, Romagnani S.Human IL-10 is produced by both

m e helper (Thl ) and lLpe 2 helper (Th2) T cell clones

and inhibits their antigen-specific proliferation and cyto-

kine production. J Immunoll993: 150: 353-360.

53. Del F'rete G, Maggi E, Parronchi P, Chretien I, TiriA, Mac-

chia D, Ricci M, Banchereau J, De Vries J Romagnani S.

IL-4 is an essential factor for the IgE synthesis induced in

virro by human T cell clones and their supernatants. J

Immunol 1988: 140: 4193-1198.

54. De Waal Malefyt R, Yssel H, de Mies JE. Direct effects of

IL- 10on subsets of hu man CD4+T cell clones and resting

T cells. Specific inhibition of IL-2 production and prolifer-ation. Immunol 1993: 150: 4754-4765.

55. De Wad Malefyt R Figdor C, Huijbens R, Mohan-Peterson

S, Bennett B, Culpepper J Dang W, Zurawski G, de Vries

JE. Effects of IL-13 on phenotype, cytokine production,

and cytotoxic function of human monocytes. J Immunol

1993: 151: 6370-6381.

56. De Wad Malefyt R, Yssel H, Roncarolo M-G, Spits H, de

Vries IE. Interleukin-10. Curr Opin Immunol 1992: 4: 314-

320.

57. Dewhirst F, Moss D, Offenbacher S, Goodson JM. Levels

of prostaglandin Ez. hromboxane, and prostacyclin in

periodontal tissues. J Periodont Res 1983: 18: 156-163.

58. Dietrich J Goodson JM, Raisz LG. Stimulation of bone

resorption by various prostaglandins in organ culture.Prostaglandins 1975: 10: 231-240.

59. Dinarello CA. Interleukin-1. Rev Infect Dis 1984: 6 51-95.

60. Dinarello CA. The biology of interleukin 1 and compari-

son to tumor necrosis factor. Immunol Lett 1987: 16 227-

232.

61. Dinarello CA. The role of interleukin-1 in host responses

to infectious diseases. Infect Agents Dis 1992: 1: 227-236.

62. Dinarello CA, Wolff SM. The role of interleukin-1 in dis-

ease. N Engl J Med 1993: 328: 106113.

63. Ding L, Shevach EM. IL-10 inhibits mitogen-induced T

cell proliferation by selectively inhibiting macrophage co-

stirnulatory function. J Immunol 1992: 148: 3133-3139.

64. Ding L, Linsley PS, Huang L-Y, Germain RN, hevach EM.

IL- 10 inhibits macrophage costimulatory activity byselectively inhibiting th e up-regula tion of B7 expression.

J Imrnunol 1993: 151: 1224-1234.

65. Distel M, Mueller C, Bluhmki E, Fries J. Safety ofmelox-

icam: a global analysis of clinical trials. Br J Rheumatol

66. Donahue RE,Wang EA, Stone DK, Kamen R, Wong GG,

Sehgal PK, Nathan DG, Clark SC. Stimulation of haema-

topoiesis in primates by continuous infusion of recorn-

binant human GM-CSE Nature 1986: 321: 872-875.

67. Dongari-Bagtzoglou A, Ebersole J. Production of inflam-

matory mediators and cytokines by human gingival

fibroblasts following bacterial challenge. J Periodont Res

1996: 31: 90-98.

68. Donnelly RE Fenton MI, Finbloom DS, Gerrard TL. Differ-

1996: 35(SUppl 1): 68-77.

134




ential regulation of IL-1 production in hum an monocytes

by IFN-y an d IL-4. J Imm uno l 199 0 145: 569-575.

69. Drevlow B, h v i s R, Haag M, Sinacore J, Jacobs C, Blosch

C, Beck C, Landay A, Moreland L, Pope R. Phase I study

of recombinant human interleukin- 1 receptor (RHUIL-

1R) administered su bcuta neou sly in patients with active

rheumatoid arthritis. Arthritis Rheum 1994: 37: S339(abstr 1070).

70. Dubois CM, Ruscetti Fw Palaszynski EW, Falk LA, Op-

penheim JJ, Keller JR. Transforming growth factor fi is a

potent inhibitor of interleukin 1 (IL-1) receptor ex-

pression: proposed mec hanism of inhibition of IL-1 ac-

tion. J Exp Med 1990: 172: 737-744.

71. DuB ois R, Awad J, Mo rrow J Roberts L, Bishop I? Regula-

tion of eicosanoid production and mitogenesis in rat in-

testinal epithelial cells by transforming growth factor-a

an d phorb ol ester. J Clin Invest 1994: 93: 493-498.

72. Eastcott W ,Yamashita K, Taubman MA, Harada Y Smith

DJ. Adoptive transfer of cloned T helpe r cells ameliorates

periodontal disease in n ude rats. Oral Microbiol Immun ol

1994:9: 284-289.73. Ebe rsole J Singer R, Steffen sen B, Filloon T, Kornm an KS.

Inflammatory mediators and immunogloblulins in GCF

from healthy, gingivitis and periodontitis sites. J Peri-

odont Res 1993: 28: 543-546.

74. Ebersole JL, Taubman MA. The protective nature of host

responses in periodontal diseases. Periodonto12000 1994:

75. El Attar TM. Prostaglandin E, in hu ma n gingiva in health

and disease and its stimulation by female sex steroids.

Prostaglandins 1976 11: 331-341.

76. El Attar T, Lin H. Prostaglandins in gingiva of patients

with periodontal disease. J Periodontol 1981: 5 2 16-19.

77. El Attar T, Lin H. Relative conversion of arachidonic acid

through lipoxygenase and cyclooxygenase pathways by

homogenates of diseased periodontal tissues. J Oral

Pathol 1983: 1 2 7-10.

78. El Attar T, Lin H, Tira D. Arachidonic acid metabolism in

inflamed gingiva an d its inhibition by anti-inflammatory

drugs. J Periodontol 1984: 55: 536-539.

79. El Attar T, Lm H. Prostaglandin E2 antagonizes gingival

fibroblast proliferation stimulated by interleukin-lp.

Prostaglandins Leukotr Essen Fatty Acids 1993: 4 9 847-

850.

80. Elliott M, Maini R. Anti-cytokine therapy in rheumatoid

arthritis. BailliBre’s Clin Rhe uma tol 1995: 9: 63 36 52 .

81. Elliot M, Maini R, Feldm an M , Kalden JR, Antoni C, Smol-en JS, eeb B, Breedveld FC, Macfarlane JD , Bijl H. Ran-

domised double-blind comparison of chimeric mono-

clonal antibody to tumor necrosis factor a cA2) ersusplacebo in rheum atoid arthritis. Lancet 1994: 344 (8930):

1105-1110.

82. Elliot M, Ma ini R, Feldm an M, Long-F ox A, Cha rles P, BijlH, Woody JN. Repeated therapy with monoclonal anti-

body to tumor necrosis factor a ( ) in patients with

rheum atoid arthritis. Lancet 1994:344 1125-1 128.83. Ellis SD, Tucci MA, Serio FG, Johnson RB. IL-12 in peri-

odon tal disease. J Dent Res 1996: 75: 322 (ab str 2440).

84. Engelhardt G, Bogel R, Schnitzler C, Utzmann R. Melox-

icam: influence on arachidonic acid metabolism. 11. In

uivo findings. Biochem Pharmacol 1996: 51: 29-38.85. Enk AH, Angeloni VL, Udey MC, Katz SI. Inhibition of

Langerhans cell antigen-presenting function by IL-10. J

Immunol 1993: 150: 4754-4765.

5: 112-141.

86. Essner R, Rhoades K, McBride WH, Morton DL, Econom-

ou JS. IL-4 dow n-regulates IL-1 and TNF gene expression

in human monocytes. J Im mu nol 1989: 142: 3857-3861.

87. Evans RT, Klausen B, Sojar HT, Bedi GS, Sfintescu C, Ram-

amurthy NS, Golub LM, Genco RJ. Immunization with

Porphyromonas (Bacteroides)gingivalis fimbriae protects

against periodontal destruction. Infect Immun 1992: 60:2926-2935.

88. Fabry Z, Sandor M, Gajewski TE Herlein JA, Waldschmidt

MM, Lynch RG, Hart MN. Differential activation of Thl

and Th2 CD4+ cells by murine brain microvessel endo-

thelial cells and smooth musclelpericytes. J Immunol

1993: 151: 3 8 4 7 .

89. Ferkol T,Kaetzel C, Davis F Gene transfer into respiratory

epithelial cells by targeting the polymeric immunoglob-

ulin receptor. J Clin Invest 1993: 92: 2394-2400.

90. Finkelman FD, Katona IM, Mosmann TR, Coffman RL.

IFN-1 regulates th e isotypes of Ig secreted d uring in vivo

humoral im mun e responses. J Immunol 1988: 140: 1022-1027.

91. Fior entino DF, Zlotn ik A, Vieira P, Mosmann TR, HowardM, Moore W, O’Garra A. IL-10 acts on the antigen-pre-

senting cell to inhibit cytokine production by Th l cells. J

Immunol 1991: 146: 3444-3451.

92. Frankenburg S, Kofsky Y Gross A. In vitro secretion of

cytokines by human mononuclear cells of individuals

durin g and after cutan eous leishmaniasis infection. Para-

site Immunol 1993: 15: 509-512.93. Freeman S, Abboud C, Whartenby KA, Packman CH, Koe-

plin DS, Moolten FL, Abraham GN. The “bystander ef-

fect.” Tumor regression when a fraction of the tumor

mass is genetically modified. Cancer Res 1993: 53: 5274-

5283.

94. Fu N asferrer JL, Seibert S, R a z A, Needleman I? The

induction and suppression of prostaglandin H2 synthase

(cyclooxygenase) n hu m an monocytes. Biol Chem 1990:

95. Fujihashi K Kono Y, Yamamoto M, McGhee JR, Beagley K

Aicher WK, Kiyono H. Interleukin p rodu ction by gingival

mononuclear cells isolated from adult periodontitis pa-

tients. J Dent Res 1991: 70: 50 (abstr 2269).

96. Fujihashi K, Yamamoto M, McGhee JR, Kiyono H. Q-pe

1I-e 2 cytokine pro du ctio n by CD4+ T cells in adult

periodontitis. J De nt Res 1994: 73: 204 (abstr 818).

97. Gaffer A, Scherl D, Afflitto J, Coleman E. The effect of

triclosan on mediators of gingival inflammation. J Clin

Periodontol 1995: 22: 480-484.

98. Gajewsk i TF, Pin nas M, Wong T, Fitch W .Murine Thl and

Th2 clones proliferate optimally in response to distinct

antigen-presenting cell populations 1 Immunol 1991: 146:1750-1758.

99. Garrison S, Holt S, Nichols E Lipopolysaccharide-stimu-

lated PGE2 release from hu m an m onocytes. J Periodontol1988: 59: 684-687.

100. Ge T, Hugh es H, Ju nq ue ro DC, Wu KK, Vanhoutte PM, Boul-

anger CM. En dothelium-depen dent contractions are as-

sociated with both augm ented expression of prostaglandin

H synthase-1 an d hypersensitivity to prostaglandin H2 inth e SHR aorta. Circ Res 1995 : 76: 1003-1010.

101. Gemmell E, Feldner B, Seym our GJ. CD45RO an d CD45RApositive cells in peripheral blood a nd periodontal lesions

before and after stimulation with Porphyrornonas g ing i -

valis a n d Fusobacteriurn nucleaturn. Oral Microbiol Im-

mu no l 1992: 7: 84-88.

265: 16737-16740.

135



Gemmell et al.

102.

103.

104.

105.

106.

107.

108.

109.

110.

111.

112.

113.

114.

Gemmell E, Kjeldsen M, Yamazaki K, Nakajima T, Aldred

MJ, Seymour GJ. Cytokine profiles of Porphyromonas gin-

givalisreactive T lymphocyte lines and clones derivedfrom I? gingivalis-infected subjects. Oral Dis 1995: 1: 139-

146.

Gemmell E, Seymour GJ. Interleukin 1, interleukin 6 a n d

transforming growth factor-@ roduction by hum an gingi-val monon uclear cells following stimu lation with Porphy

romonaS gingivalis a n d Fusobacterium nucleaturn J Peri-

odo nt Res 1992: 28: 122-129.

Gemmell E, Seymour GJ. Modulation of immune re-

sponses to periodontal bacteria. Cum Opin Periodontol

Genco RJ, Mashimo PA, Krygier G, Ellison SA. Antibody-

mediated effects on the periodontium. J Periodontol

1974: 45: 330-337.

Genco RJ, Zam bon JJ, Christersson LA. The origin of peri-

odontal infections. Adv Dent Res 1988: 2: 245-259.

Geng Y, Blanco F, Cornelisson M, Lotz M. Regulation of

cyclooxygenase-2 expression in normal human articular

chondrocytes. J Immunol 1995: 155: 79 64 01 .Ghezzi P, Dinarello CA. L-1 induces IL - 1 . 3. Specific inhi-

bition of IL-1 production by IFN-y. J Immunol 1988: 140:

42364244.

Gierse JK$Haus er SD, Creely DP, Koboldt C,Rangwala SH,

Isajson PC, Siebert K. Expression a nd selective inhibition

of the constitutive and inducible forms of human cyclo-

oxygenase. Biochem J 1995: 305(part 2): 479-484.

Gilboa E. Immunotherapy of cancer with genetically

modified tum or vaccines. Semin Oncol 1996: 23: 101-107.

Goldhaber F Tissue culture studies of bone as a model

system for periodontal research. J Dent Res 1971: 50: 278-

285.

Goldhaber P, Rabadjija L, Beyer WR, Kornhauser A. Bone

resorption in tissue culture and its relevance to peri-odon tal disease. J Am Den t Assoc 1973: 87: 1027-1033.

Golumbeck PT, azenby AJ, Levitsky HI, Jaffee LM, Karas-

uyama H, Baker M, Pardoll DM. Treatment of established

renal cancer by tumour cells engineered to secrete in-

terleukin-4. Science 1991: 254: 713-716.

Gomes BD, Hausmann E, Wienfeld N, De Luca C. Prosta-

glandins: bon e resorption stimu lating factors released

from mon key g ingiva. Calcif Tissue Res 1976 19: 285-293.

1994: 28-38.

115. Goodson JM, Derwhirst E Brunetti A. Prostaglandin E2

levels and human periodontal disease. Prostaglandins

1974: 6: 81-85.

116. Graham BS, Henderson GS, Tang Y-W, Lu X, Neuzil KM,

Colley DG. Priming immunization determines T helper

cytokine mRNA expression pa tterns i n lungs of m ice chal-lenged with respiratory syncytial virus. J Immunol 1993:

117. Granowitz EV Clark BD. Effect of interleukin-1 ( I L - 1 )

blockade o n cytokine synthesis: IL- 1 receptor a ntagonist

inhibits IL-1 induced cytokine synthesis and blocks the

binding of IL-1 o its type 11 receptor on human mono-

cytes. Blood 1992: 79: 2356-2363.

118. Grimm E, Mazumder A, Zha ng H, Rosenberg S.Lympho-

kine-activated killer cell phenomenon. Lysis of natural

killer-resistant fresh solid tum or cells by interleukin 2-

activated autologous human peripheral blood lympho-

cytes. J Exp Med 1982: 155: 1823-1841.

119. Griswold DE, Hillegass LM, Breton JI, Esser KM, Adams

JL. Differentiation in vivo of classical non -steroid al antiin-

151: 2032-2040.

120.

121.

122.

123.

124.

125.

126.

127.

128.

129

130.

131.

132.

133.

134.

flam mato ry drug s from cytokine-suppressive a ntiin-

flammatory drugs and other pharmacological classes

using mouse tumour necrosis factor alpha production.

Drugs Exp Clin Res 1993: 19: 243-248.

Griswold DE, M arshall P J, Lee JC, Webb EF, Hillegass LM,

Wartell 1, Newton J Jr, Han na N. Pharm acology of the pyr-

roloimidazole, SK&F 105809.11. Antiinflammatory activityand inhibition of mediator production in vivo. Biochem

Pharmacol 1991:4 2 825-831.

Grossman M, Raper S , Kozarsky K, Ste in E, Eng elhardt J

Muller D, Lupien PJ, Wilson JM. Successful ex vim gene

therapy directed to liver in a patient with familial hyper-

cholesterolaemia. Nature Genet 1994 6: 335-341.

Grove KL, Guo X Liu SH, Gao Z, Ch u CK, Ch eng YC. An-

ticancer activity of beta-L-dioxolane-cytidine, novel

nucleoside analogue with the u nnatural L configuration.

Cancer Res 1995: 55: 3008-3011.

Hamblin AS. In: Male D, ed. Cytokines and cytokine re-

ceptors. Oxford: Oxford University Press, 1993.

Ha mm erb erg C, Arend W, Fisher G, Chan L, Berger A,

Haskill J, Voorhees J, Co oper K. Interleukin-1 receptor an-tagonist in normal and psoriatic epidermis. J Clin Invest

Hanania E, Fu S, Zu Z, Hegewisch Becker S , Korbling M,

Hester J, Durett A, Andreeff M, Mechetner E, Holzmayer

T, Roninson I, Giles E, Bere nson R, Heimfeld S,Deisscroth

A. Chem otherapy resistance to taxol in clonogenic pro-

genitor cells following transduction of CD34 selectedmarrow and peripheral blood cells with a retrovirus that

contai ns the MDR-1 chemo therap y resistance gene. Gene

Ther 1995: 2: 285-294.

Hanania E, Kavanagh J, Hortobagyi G, Giles R, Champlin

R, Deisseroth A. Recent advances in the application of

gene therapy to hu ma n disease. Am J Med 1995: 99: 537-

552.Harrell J Stein S. Prostaglandin E2 regulates gingival

mononuclear cell immunoglobulin production. J Peri-

odontol 1995: 66: 222-227.

Harvey W, Bennett A. Prostaglandins in bone resorption.

Boca Raton, F L CRC Press, 1988.

Heasman P, Benn DK, Kelly F: Seymour R, Aitken D. The

use of topical flurbiprofen as an adjunct to non-surgical

management of periodontal disease. J Clin Periodontol

1993: 20: 457-464.

Heasman F Collins J, Offenbacher S. Changes in crevic-

ular fluid levels of in terleuk in-lp, leukotriene B4, rosta-

glandin E2, thromboxane B2 and tumour necrosis factor

n experimental gingivitis in humans. J Periodont Res

Heasman P, Offenbacher S , Collins I, Edwards G, Seymour

R. Flurbiprofen in the prevention and treatment of experi-

men tal gingivitis. J Clin Periodontol 1993: 20: 732-728.

Heas man PA, Seymour R. The effect of a systemically-ad-

ministered non-stero idal anti-inflammatory drug

(flurbiprofen) on experimental gingivitis in humans. J

Clin Periodontol 1989: 16: 551-556.

Heasman P, Seymour R, Kelly P The effect of systemicdly-

administered flurbiprofen as an adjunct to toothbrushing

on resolution of experim ental gingivitis. J Clin Peri-

odontol 1994: 21: 166-170.

Hendley TM, Steed RB, Galbraith GMF Interleukin-lp

gene expression in human oral polymorphonuclear

leukocytes. J Periodontol 1995: 66: 761-765.

1992:90: 571-583.

1993: 28: 241-247.

136




135. Higuchi M, Aggarwal BB. Modulation of two forms of tu-

mor necrosis factor receptors and their cellular response

by soluble receptors and their monoclonal antibodies. J

Biol Chem 1992: 267: 20892-20899.

136. Honig J, Rordorf-Adam C, Siegmund C, Wiedemann W,

bard E Interleukin-1 beta (IL-lp) concentration in gingi-

va tissue from periodontitis patients and healthy controlsubjects. J Periodont Res 1989: 24: 362-367.

137. HoogerbruggeI:Vassen J, BeusechannV, Valerio D. Treat-

ment of patients with SCID due to ADA deficiency by

autologous transplantation of genetically-modified bone

marrow cells. Hum Gene Ther 1992 3 553-558.

138. Howard M, O'Garra A. Biological properties of Interleukin

139.

140.

141.

142.

143.

144.

145.

146.

147.

148.

149.

150.

151.

152.

153.

10. Immunol Today 1992 13: 196-200.

Howell TH. Blocking periodontal disease progression with

anti-inflammatory agents. J Periodontol 1993: 6 4 828-

833.

Howells GL. Cytokine networks in destructive periodontal

disease. Oral Dis 1995:1: 266-270.

Hughes FJ, Howells GL. Interleukin-6 inhibits bone for-

mation in uitro. Bone Min 1993: 21: 21-28.Hyams IS, Fitzgerald JE, Wyzga N, Muller R, Treem WR,

JustinichCJ, Kreutzer DL. Relationship of interleukin-1re-

ceptor antagonist to mucosal inflammation in inflamma-

tory bowel disease. J Pediatr Gastroenterol Nutr 1995:21:

419-425.

Inoue T, Asano Y,Matsuoka S,Furutani-SeikiM, Aizawa

S, Nishimura H, Shirai T, Tada T. Distinction of mouse

CD8+ suppressor effector T cell clones from cytotoxic T

cell clones by cytokine production and CD45 isoforms. J

Isakson I: Siebert K, Masferrer J, Salvemini D, Lee L,

Needleman P. Discovery of a better aspirin. Adv Prosta-

glandin Thromboxane Ledcot Res 1995: 2 3 49-54.

Ishii T, Mahanonda R, Seymour GI. The establishment ofhuman T cell lines reactive with specific periodontal bac-

teria. Oral Microbiol Immunol 1992: 7: 225-229.

Ito H-0 , Shuto T, Takada H, Koga T, Aida Y,HirataM, Koga

T. Lipopolysaccharides from Potphyromonas gingiualis,

Prevotella intermedia and Actinobacillus actinomycetem-

comitans promote osteoclast differentiation in vim.Arch

Oral Biol 1996: 41: 439-444.

Jeannin I: DelnesteY,Life P. GauchatJE Kaiserlian D, Bon-

nefoy JY. Interleukin-12 increases interleukin-4 produc-

tion by established human Tho and Th2-lie T cell clones.

Eur J Immunol 1995: 25: 2247-2252.

Jinquan T, Grenhoj Larsen C, Gesser B, Matsushima K,

Thestrup-PedersenT.Human It-10 is a chemoattractant

for CD8+ T lymphocytes k d n inhibitor of IL-8-inducedCD4+ T lymphocyte migration. J Immunol 1993: 151:

4545-4551.

Jones D, Carlton D, McIntyre T, Zimmerman G, Prescott

S.Molecular cloning of human prostaglandin endoperoxi-

dase synthase type 11 and demonstration of expression in

response to cytokines. J Biol Chem 1993: 268: 9049-9054.

Karatzas S, Novak MJ, Blieden TM. Cytokine production

by Porphyromonas gingivalisspecific human T cells. J

Dent Res 1996 75: 322 (abstr 2435).

Kelso A. Cytokines in infectious disease. Aust Microbiol

Kelso A. Thl and Th2 subsets: paradigms lost? Immunol

Today 1995: 16: 374-379.

Kelso A, Troutt AB, Maraskovsky E, Gough NM, Morris L,

IIIUINUIOI1993: 150: 2121-2128.

1990: 11: 372-376.

154.

155.

156.

157.

158.

159.

160.

161.

162.

163.

164.

165.

166.

Pech MH, Thomson JA. Heterogeneity n lymphokine pro-

files of CD4+ and CDB+ T cells and clones activated in

vivo and in vitro. Immunol Rev 1991: 123: 85-114.

Kesavalu L, Ebersole JL, Machen RL, Holt SC. Porphyro-

monas gingivalis virulence in mice: induction of immun-

ity to bacterial components. Infect Immun 1992: 60:

1455-1464.Kimura S, Fugimoto N, Okada H. Impaired autologous

mixed-lymphocyte reaction of peripheral blood lympho-

cytes in adult periodontitis. Infect Immun 1992:59: 4418-

4424.

Klein DC, Raisz LG. Prostaglandins: stimulation of bone

resorption in tissue culture. Endocrinology 1970: 86:

1436-1440.

Klein T, Nusing RM, Pfeilschifter J Ullrich V.Selective in-

hibition of cyclooxygenase 2. Biochem Pharmacol 1994:

48: 1605-1610.

Knight D, m n h H, Le J, Siege1 S, Shealy D, McDonough

M, Scallon B, Moore MA, Vicek J, Daddona P Ghrayeb

J. Construction and initial characterization of a mouse-

human chimeric anti-TNF antibody. Mol Immunol 1993:

Kobayashi M, Fitz L, Ryan M, Hewick RM, Clark SC, Chan

S, Loudon R, Sherman E Perussia B, Tiinchien G. Identi-

fication and purification of natural killer cell stimulatory

factor (NKSF) a cytokine with multiple biologic effects o n

human lymphocytes.J Exp Med 1989 70 : 827-845.

Koq ON, Allay JA, Lee K, Davis BM, Reese JS, Gerson SL.

Transfer of drug resistance genes into hematopoietic pro-

genitors to improve chemotherapy tolerance. Semin On-

col 1996: 23: 46-65.

Koch AE, Kunkel SL, Harlow LA, Johnson B, Evanoff HL,

Haines GK, Burdick MD, Pope RM, StrieterRM. Enhanced

production of rnonocyte chemoattractant protein-1 in

rheumatoid arthritis. J Clin Invest 1992: 90: 772-779.KoideM, Suda S,SaitohS,OfujiY Suzuki T,Yoshie H, Takai

M, OnoY, TaniguchiY, Hara K. In vivoadministration of IL-

l p accelerates silk ligature-induced alveolar bone resorp-

tion in rats. J Oral Pathol Med 1995: 2 4 420-434.

Kujubu D, Fletcher B, Vamum B, Lim R, Henchman H.

TIS10, a phorbol ester tumor promoter-inducible mRNA

from Swiss 3T3 cells, encodes a novel prostaglandin syn -

thaselcyclooxygenase gene. J Biol Chem 1991: 266:

12866-12872.

Kupper TS, Ballard DW, Chua AO, McGuire JS, Flood PM,

Horowitz MC, Langdon R, Lightfoot L, Gubler U. Human

keratinocytes contain mRNA indistinguishable from

monocyte interleukin- a and fi mRN4 keratinocyte epi-

dermal cell-derived thymocytes activating factor is ident-ical to interleukin-1. J Exp Med 1986: 164: 2095-2100.

Kutsch CL, Norris DA, ArendW umor necrosis factor-

alpha induces interleukin-1 alpha and interleukin-1 re-

ceptor antagonist production by cultured human kera-

tinocytes.J Invest Dermatol 1993: 101: 79-85.

Lamont AG, Adorini L. IL-12: a key cytokine in immune

3 0 1443-1453.

.~regulation. Immunol Today 1996: 17: 214-217.

167. Laneuville 0, Breuer DK, Dewitt DL, Hla T Funk CD,

SmithWL. Differential inhibition of human prostaglandin

endoperoxidase H synthases-1 and -2 by nonsteroidal

anti-inflammatory drugs. J Pharmacol Exp Ther 1994:

168. Larkin M. Promising results reported for lung cancer gene

271: 927-934.

therapy. Lancet 1996: 34 8 671.

137



Gemmell et al.

169. Lattime E,Lee S , Eisenlohr L, MastrangeloM. In situ cyto-

kine gene transfection using vaccinia virus vectors. Semin

Oncol 1996: 23:88-100.

170.Le J Vilcek J. Biology of disease. lbmor necrosis factor

and interleukin 1. Cytokines with multiple overlapping

biological activities. Lab Invest 1987: 3: 234.

171. Lee JC, Young PR. Role of CSBIp381RK stress responsekinase in LPS and cytokine signaling mechanisms. J Leu-

koc Biol 1996: 59: 152-157.

172. Lee S, Soyoola E, Chanmugam P, Hart S, Sun W Zhong

H, Liou S, Simmons D, Hwang D. Selective expression of

mitogen-inducible cyclooxygenase in macrophages

stimulated with lipopolysaccharide. J Biol Chem 1992:

267: 25934-25938.

173.Lewis RA. Interactions of eicosanoids and cytokines in

immune regulation. Adv Prostaglandin Thromboxane

Leukot Res 1990:20:170-178.

174.Lloyd AR,Oppenheim JJ. Polys lament: The neglected role

of the polymorphonuclear neutrophil in the afferent limb

of the immune response. Immunol Today 1992: 13: 169-

172.175.Loning T, Albers H, Lisboa B, Burkhardt A, Caselitz I.

Prostaglandin E and local immune response in chronic

periodontal disease. Immunohistochernicaland radioim-

munological observations. J Periodont Res 1980: 15: 525-

35.

176. Lopatin DE, lackburn E. Avidity and titer of immuno-

globulin G subclasses to P o r p h y r o m o m gingivalis in

adult periodontitis patients. Oral Microbiol Immunol

177.Lundgren M, Persson U, Larsson P, Magnusson C, Smith

CIE, HammarstrOm L, SeverinsonE. Interleukin4 nduces

synthesisof IgE and IgG4 in human B cells. Eur J Immun-

178.Lupton S Printon L, Kalberg V, Overall R. Dominant posi-tive and negative selection using a hygromycin phospho-

transferase thymidine kinase fusion gene. Mol Cell Biol

1991: 11: 3374-3378.

179.MacFarlane GD,Herzberg MC, Wolff LF,Hardie NA. Re-

fractory periodontitis associated with abnormal polymor-

phonuclear leukocyte phagocytosis and cigarette smok-

ing, 1Periodontol 1992: 63: 908-913.

180.Mahanonda R Seymour GJ, Powell LW Good ME Halliday

W. Effect of initial treatment of chronic inflammatory

periodontal disease on the frequencyof peripheral blood

T-lymphocytes specific to periodontopathic bacteria. Oral

Microbiol Immunol 1991:6: 21-227.

181.Mangan DF, Mergenhagen SE, Wahl SM. Apoptosis in hu-

man monocytes: possible role in chronic inflammatorydiseases. J Periodontol 1993:64: 61-466.

182. Mangan DF,Robertson B, Wahl SM. IL-4 enhances pro-

grammed cell death (apoptosis) in stimulated human

monocytes.J Immunol 1992: 148: 1812-1816.

183.Manhart SS,Reinhardt RA, Payne JB, Seymour GI, Gem-

mell E, Dyer IK Petro TM. Gingival cell IL-2 and IL-4 in

early-onset periodontitis. J Periodontol 1994: 65: 807-

813.

184. March CJ, Mosley B, Larsen A, Cerretti DP, Braedt G, Price

V, Gillis S , Henney CS, Kronheim SR, Grabstein K Conlon

P, Hopp T, Cosman D. Cloning, sequence and expression

of two distinct human interleukin- complementary

DNAs. Nature 1985: 315: 641-647.

185. Marks Jr S Miller S . Local infusion of prostaglandin E l

1992: : 332-337.

01 1989: 19: 1311-1315.

stimulates mandibular bone formation in uiuo. J Oral

Pathol 1988:17: 00-505.

186. Marks S,Miller S . Local delivery of prostaglandin El in-

duces periodontal regeneration in adult dogs. J Periodont

Res 1994:29:103-108.

187. Martin D, Near SL. Protective effect of the interleukin-1

receptor antagonist (IL-Ira) on experimental allergic en-cephalomyelitis in rats. J Neuroimmunol 1995: 61: 41-

245.

188. Masada MP, Persson R, Kenney JS, Lee SW, Page RC, Mi-

son AC. Measurement of interleukin-la and -1p n gingi-

val crevicular fluid implication for the pathogenesis of

periodontal disease. J Periodont Res 1990: 25: 156-163.

189. Mastrangelo M , Berd D, Nathan E Lattime E. Gene ther-

apy for human cancer: an essay for clinicians. Sem Oncol

190. Matsuki Y, Yamamoto T, Hara K. Detection of inflamrna-

tory cytokine messenger-RNA (mRNA)-expressing cells in

human inflamed gingiva by combined in situ hybridiza-

tion and immunohistochemistry. Immunology 1992: 7 6

42-47.191. Matsuki Y, Yamamoto T,Hara K. Localizationof interleu-

kin-1 (IL-1) mRNA-expressing macrophages in human in-

flamed gingiva and IL-1 activity in gingival crevicular

fluid. J Periodont Res 1993: 28: 35-42.

192. Mavilio E Ferrari G, Rossini S , Nobili N, Bonini C, Casorati

G, Traversari C, Bordignon C. Peripheral blood lympho-

cytes as target cells of retroviral vector-mediated gene

transfer. Blood 1994: 83: 1988-1997.

193.McKenzie AN, Culpepper JA, de Wad Malefyt R, Briere F,

Punnonen J Aversa G , Sat0 A, Dang W, Cocks BG, Menon

S , de Vries JE, Banchereau J Zurawski G. Interleukin 13,a

T-cell-derived cytokine that regulates human monocyte

and B-cell function. Proc Natl Acad Sci U S A 1993: 90:

3735-3739.194. Meghji S, Henderson B, Wilson M. High-titer antisera

from patients with periodontal disease inhibit bacterial

capsule-induced bone breakdown. J Periodont Res 1993:

28: 115-121.

195. Meikle MC, Heath JK Reynolds J]. Advances in under-

standing cell interactions in tissue resorption. Relevance

to the pathogenesis of periodontal diseases and a new

hypothesis. J Oral Path01 1986 15:239-250.

196. Meikle MC, Atkinson SJ, Ward RV, Murphy G, Reynolds JJ.

Gingival fibroblasts degrade type 1 collagen films when

stimulated with tumor necrosis factor and interleukin 1.

Evidence that breakdown is mediated by metalloprotein-

ases. J Periodont Res 1989:24 07-213.

197. Mendieta C, Reeve C, Romero J. Biosynthesisof prosta-glandins in gingiva of patients with chronic periodontitis.

J Periodontol 1985: 5 6 4-47.

198.Mingari MC, Moretta A, Maggi E, Pantaleo G, Gerosa F,

RomagnaniS , Moretta L. Frequent coexpression of cytoly-

tic activity and lymphokine production among human T

lymphocytes. Production of B cell growth factor and in-

terleukin 2 by T8+ and T4' cytolytic clones. Eur J Immun-

01 1984: 14: 1066-1069.

199. Mitchell J Akarasereenont P, Thiemermann C, Flower R,

Vane J. Selectivity of nonsteroidal antiinflammatory drugs

as inhibitors of constitutive and inducible cyclooxygen-

ase. Proc Natl Acad SciU S A 1993:90: 1693-11697.

200. Miyamoto T, Ogino N , Yamamoto S , Hayaishi 0. Purifi-

cation of prostaglandin endoperoxide synthetase from

1996: 23: 4-21.

138



Cytokines and p rostaglandin s in periodontal disease

bovine vesicular gland microsomes. J Biol Chem 1976:

201. Miyauchi M, Ijuhin N, Nikai H, Takata T, Ito H, Ogaw a I.

Effect of exogenously applied prostaglandin E2 on al-

veolar bon e loss-histometric analysis. J Periodontol 1992:

63: 405-411.

202. Modlin RL, Nutman TB. Type 2 cytokines and negativeimmune regulation in human infections. Cun Opin Im-

munol 1993: 5: 511-517.

203. Moore MA. The clinical use of colony stimulating factors.

Annu Rev Immu nol 1991: 9: 159-191.

204. Mo reland L, Ma rgolie s G, Heck L, Saway P: Jacobs C, Beck

C, Blosch C, Kooperman W. Soluble tumor n ecrosis factor

receptor (sTNFR) results of a phase I dose-escalation

study in patients with rheumatoid arthritis. ArthritisRheum 1994: 37: S295 (abstr 813).

205. Morris AG. Interfero ns Imm unolog y 1988: l(supp1 ): 43-

45.

206. Mosmann TR. Cytokines: is there biological meaning?

Curr Opin Immunol 1991: 3: 311-314.

207. Mosmann TR, Coffman RL.TH1 an d TH2 cells: differentpatterns of lymphokine secretion lead to different func-

tional properties. Annu Rev Imm unol 1989: 7: 145-173.

208. Mosmann TR, Sad S. The expanding universe of T-cell

subsets: Thl, Th2 and more. Immunol Today 1996: 17:

138-146.

209. Mulligan R. The basic science of gene therapy Science

1993: 26 0 926-932.

210. Mundy GR. Inflammatory’mediators a nd th e destruction

of bone. J Periodont Res 1991: 2 6 213-217.

211. Nabel G, Nabel E, Yang Z, Fox BA, Plautz GE, Gao X, Hu-

ang L, Shu S, Gordon D, Chang AE. Direct gene transfer

with DNA liposome complexes in melanoma: Expression,

biologic activity and lack of toxicity in humans. Proc Natl

Acad Sci U S A 1993: 9 0 11307-11311.212. Nakashima K, Roehrich N, Cimasoni G. Osteocalcin,

prostaglandin E2 and alkaline phosphatase in gingival

crevicular fluid: their relations to periodontal status. J Clin

Periodontol 1994: 21: 327-333.

213. Nathan C, Kaplan G, Levis W, Nusrat A, Witmer M, Sher-

win S, Job C, Horowitz C, Ste inm ann R, Cohn Z. Local an d

systemic effects of intradermal recombinant interferon-

gamma in patients with lepromatous leprosy. N Engl J

Me d 1986: 315: 6-15.

214. Nell A, Matejka M, Solar P, Ulm C, Sinzinger H. Evidence

that cyclosporine inhibits periodontal prostaglandin I2

synthesis. J Periodont Res 1996: 31: 131-134.215. Nicola NA. Guidebook to cytokines and their receptors.

Oxford: Oxford University Press, 1994.216. Nienhuis A, Donahue R, Karlsson S, Clark S, Agricola B,

Antinoff N, Pierce J , f i rn er R Anderson W, Nath an D. Re-

combinant human granulocyte-macrophage colony-

stimulating factor (GM-CSF) shorte ns the p eriod of ne u-

tropenia after autologous bon e marrow transplantation in

a primate model. J Ctin Invest 1987: 80: 573-577.

217. Nish ihara T, Ohs aki Y Ueda N, Saito N, Mundy GR. Mouse

interleukin-1 receptor antagonist induced by Actino-

bacillus actinomycetemcomitans lipopolysaccharide

blocks th e effects of interleukin-1 on b one resorption a nd

osteoclast-like cell formation. Infect Immun 1994: 62:

390-397.

218. Norm an J, Franz M, Messina J, Riker A, Fabri PI, Rosem ur-

gy AS, GowerWR r. Interleukin-1 receptor antagonist de-

251: 2629-2636.

creases severity of experimental acute pancreatitis.

Surgery 1995 : 117: 648-655.

219. Offenbacher S, Farr D, Goodson J. Measurement of

prostaglandin E in crevicular fluid. J Clin Periodontol

220. Offenbacher S Odle B, Braswell L, Johnson H, Hall C,

McClure H, Orkin J, Strobert E, Green M. Changes incyclooxygenase metabolites in experimen tal periodontitis

in Macam mu la th J Periodont Res 1989: 24: 63-74.

221. Offenbacher S, Odle B, Green M, Mayambala C, Smith M,

Fritz M, van Dyke T, Yeh K, Sena E Inhibition of human

periodontal prostaglandin E2 synthesis with selected

agents. Agen ts Actions 1990: 29: 232-238.

222. Offenbacher S, Odle B, Van Dyke T. The use of crevicular

fluid prostaglandin E2 evels as a predictor of periodontal

attachment loss, J Period ont Res 1 98 6 21: 101-112.

223. Offenbacher S, Williams R, Jeffcoat M, Howell T, Odle B,

Smith M, Hall C, Johnson H, Goldhaber F? Effects of

NSAIDs on beagle crevicular cyclooxygenase metabolites

and periodontal bon e loss. J Periodont Res 1992: 27: 207-

213.224. O’Garra A. Peptide regulatory factors. Interleukins an d the

imm une system. Part 1. Lancet 19 89 1:943-946.

225. O’GarraA. Peptide regulatory factors. Interleukins a nd the

imm une system 2. Lancet 1989 1: 1003-1005.

226. Ogawa T, Kushumoto Y, Hamada S, McG hee JR, Kiyono

H. Bacteroides gingivalisspecific serum IgG and IgA sub-

class antibodies in periodontal disease. Clin Exp Immunol

227. Ogiso B, Hughes E Davies J, McCulloch A. Fibroblastic

regulation of osteoblast function by prostaglandins. Cell

Signal 1992: 4: 627-4539.

228. Ok uda K, Kato T, Na ito Y, Kikuchi Y, Takazoe I. Suscepti-

bility of Bacteroides gingivalis to bactericidal activity of

huma n s e rum. J Dent Res 1986: 65: 1024-1027.229. O ppen heim JJ, Zachariae COC, Mukaida N, Matsushima

K. Properties of the novel proinflammatory supergene

“intercrine” cytokine family. Annu Rev Immunol 1991: 9:

617-648.

230. Orange JS, Wolf SF, Biron CA.Effects of IL-12 on the re-

spon se an d susceptibility to experim ental viral infections.

J Im mu nol 1994: 152: 1253-1264.

231. Otterness IG, Bliven ML, Downs JT, Natoli EJ, Hanson DC.

Inhibition of interleukin 1 synthesis by tenidap: a new

drug for arthritis. Cytokine 1991: 3:277-283.

232. O’Sullivan M, Chilton F Huggins E, McCall C. Lipopoly-

saccharide priming of alveolar macrophages for en-

hanced sythesis of prostanoids involves induction of a

novel prostaglandin H synthase. J Biol Chem 1992: 267:

233. Page RC. The role of inflammatory mediators in the

pathogenesis of periodontal disease. J Periodont Res 1991:

2 6 230-242.

Canto r H. Differential induc -

tion of interferon gene expression after activation of

CD4+ T cells by conventional antig en and M ls supera nti-

gen. Proc Natl Acad Sci U S A 1991: 88:273G2739.

235. Payne JB, Reinhardt FIA, Masada MI: DuBois LM, Allison

AC. Gingival crevicular fluid IL-8; correlation with local

IL-1 levels and patient estrogen status. J Periodont Res

1993: 28: 451-4 53.

236. Perregaux DG, Dean D, Cro nan M. Connelly P, Gabel C A.

Inhibition of interleukin-1 beta production by SKF86002:

1981: 8: 369-367.

19 90 82: 318-325.

14547-14550.

234. Patarca R, Wei FY, Iregui

139



Gemmell et al.

237.

238.

239.

240.

241.

242.

243.

244.

245.

246.

247.

248.

249.

250.

251.

252.

253.

evidence of two sites of in vitro activity and of a time and

system dependence. Mol Pharrnacol 1995: 48: 433-442.

Persson GR, Engel D, Whitney C, Darveau R, Weinberg A,

Brunsvold M , Page RC. Immunization against Porphyo-

monas gingivalis inhibits progression of experimental

periodontitis in nonhuman primates. Infect Immun 1994:

62: 1026-1031.Perussia B, Chan SH, D’Andrea A, Tsuji K, Santoli D, Pos-

pisil M, Young D, Wolf SETrinchieri G. Natural killer NU

cell stimulatory factor or IL-12 has differential effects on

the proliferation of TCR-alpha beta+, TCR-gamma delta+

T lymphocytes, and NK cells. 1 lmmunol 1992: 149: 3495-

3502.

Pfeilschifter J. Transforming growth factor-p. In:Haben-

icht A, ed. Growth factors, differentiation factors, and

cytokines. Berlin: Springer-Verlag, 1990: 56-64.

Pilon M, Williams-Miller C, Cox DS. Interleukin-2 levels

in gingival crevicular fluid in periodontitis. I Dent Res

1991: 70:550 abstr 2270).

Platt D, Crosby RG, Dalbow MH. Evidence for the pres-

ence of immunoglobulins and antibodies in inflamedperiodontal tissues. J Periodontol 1970: 41: 215-222.

Podolsky DK. Inflammatory bowel disease. Part 1. N Engl

J Med 1991: 325: 928-937.

Powrie F, Coffman RL.Cytokine regulation of T-cell func-

tion: potential for therapeutic intervention. Lmmunol To-

day 1993: 14: 270-274.

Prabhu A, Michalowicz, Mathur A. Detection of local and

systemic cytokines in adult periodontitis. I Periodontol

1996: 6 7 515-522.

Punnonen 1 Aversa G, Cocks BG, McKenzie AN Menon

S, Zurawski G, de Wad Male@ R, de Vries JE. Interleukin

13 induces interleukin 4-independent IgG4 and IgE syn-

thesis and CD23 expression by human B cells. Proc Natl

Acad Sci U S A 1993:90: 3730-3734.Qwamstrijm EE, MacFarlane SA, Page RC. Effects of in-

terleukin-1 on fibroblast extracellular matrix, using a 3-

dimensional culture system. 1Cell Physiol 1989: 139: 501-

508.

Raisz LG.Physiologic and pharmacologic regulation of

bone resorption. N Engl J Med 1970 282: 909-916.

Rankin E, Choy E. Kassimos D, Kingsley GH, Sopwith A M

Isenberg DA, Panayi GS. The therapeutic effects of an en-

gineered human anti-tumour necrosis factor alpha anti-

body CDP571) in rheumatoid arthritis. Br J Rheurnatol

1995: 34: 334-342.

Re F, Mengozzi M, Muzio M, Dinarello CA,Mantovani A,

Colotta E Expression of interleukin-1 receptor antagonist

(IL- Ira) by hum an circulating polymorphonuclear cells.Eur J Immunol 1993: 23: 570-573.

Reddi K, Wilson M, Nair S, Poole S, Henderson B. Com-

parison of the pro-inflammatory cytokine-stimulating ac-

tivity of the surface-associated proteins of peri-

odontopathic bacteria. J Periodont Res 1996:31: 120-130.

Reinhardt RA Masada ME KaldahlWB, uBois LM Korn-

man KS, Choi JI, Kalkwarf KL. AUison AC. Gingival fluid

IL-1 and 1L-6 levels in refractory periodontitis. J Clin Peri-

odontol 1993:20: 225-231.

Reinhardt RA, McDonald TL, Bolton RW, Dubois LM. Kal-

dahl WB. IgG subclasses in gir~gival revicular fluid from

active versus stable periodontal sites. J Periodontol 1989:

Richards D, Rutherford RB. The effects of interleukin-1 on

60: 4-50.

254.

255.

256.

257.

258.

259.

260.

261.

262.

263.

264.

265.

266.

267.

268.

269.

270.

collagenolytic activity and prostaglandin-E secretion by

human periodontal-ligament and gingival fibroblast. Arch

Oral Biol 1988: 33: 237-243.

Riddell S, Russer P, Greenberg P.Cytotoxic T cells specific

for CW . a potential therapy for immunocompromised

patients . Rev Infect Dis 1991: 13 suppl 11): S966S973.

Rissen R, Rahimizadeh H, Blessing E, Takeshita S, Barry Jh e r . Arterial gene transfer using pure DNA applied d i-

rectly to a hydrogel-coated angioplasty balloon. Hum

Gene Ther 1993: 4 749-758.

Rijcken M, Milller KM, Saurat J-H, Milller I, Louis JA, Cer-

ottini J-C, Hauser C. Central role for TCRlCD3 ligation in

the differentiation of CD4+ T cells toward a Thl or Th2

functional phenotype. 1 Immunoll992: 148: 47-54.

Rijcken M, Saurat JH, Hauser C. A common precursor for

CD4+ T cells producing IL-2or IL-4. J Immunol 1992: 148:

Romagnani S. Human TH1 and TH2 subsets: regulation

of differentiation and role in protection and immuno-

pathology. Int Arch Allergy Immunol 1992: 98: 279-285.

Roodman GD. Interleukin-6: an osteotropic factor? J BoneMiner Res 1992: : 475-478.

Rosa F Fellows M. Effect of gamma-interferon on MHC

antigens. Immunol Today 1984:9: 261-262.

Rosenberg S, Lotze M, Mud L, Leitman S, Chang A, Et-

tinghausen S, MatoryY,Skibber J Shiloni E, Vetto J, Seipp

C, Simpson C, Reichert C. Observations on the systemic

administration of autologous lymphokine-activated killer

cells and recombinant interleukin-2 to patients with

metastatic cancer. N Engl J Med 1985: 313 1485-1492.

Rosenkoetta M, Reder AT, Oger JJ, Antel JI?T-cell regula-

tion of polyclonally induced immunoglobulin secretion in

humans. I Immunol 1984: 132: 1779-1783.

Rossomando EF, Kennedy JE, Hadjimichael J. Tumor ne-

crosis factor alpha in gingival crevicular fluid as a possibleindicator of periodontal disease in humans. Arch Oral

Biol 1990:35: 431-434.

Rousset E Garcia E, Defrance T, Peronne C, Vezzio N, Hsu

DH, Kastelein R, MooreW anchereau J. nterleukin 10

is a potent growth and differentiation factor for activated

human B lymphocytes. Roc Natl Acad SciU S A 1992: 89:

1890-1 893.

S a f f a r J Lasfargues J. A histometric study of the effect of

indomethacin and calcitonin on bone remodelling in

hamster periodontitis. Arch Oral Biol 1984: 2 9 555-558.

Saito S, Ngan P, Saito M, Lanese R, Shanfeld J Davidovitch

Z. Interactive effects between cytokines on PGE produc-

tion by human periodontal ligament fibroblasts in vitro.

Dent Res 1990: 69: 1456-1462.Saito S, Rosol T, Saito M, N g i h P, Shanfeld J, Davidovitch

Z. Bone-resorbing activity and prostaglandin E produced

by human periodontal ligament cells in vitro. J Bone

Miner Res 1990: 5 : 1013-1018.

Saito S, Saito M, Ngan P, Lanese R, Shanfeld J Davidovitch

Z. Effects of parathyroid hormone and cytokines on

prostaglandin E synthesis and bone resorption by human

periodontal ligament fibroblasts. Arch Oral Biol 1990: 35:

845-855.

Salgame P, Abrams JS Clayberger C, Goldstein H, Convit

I , Modlin RL, Bloom BR. Differing lymphokine profiles of

functional subsets of human CD4+ and CD8+ T cell

clones. Science 1991: 254: 279-282.

Scharton Kersten T, Scott I? The role of the innate im-

1031-1036.

140



Cytokines an d prostagla ndins in periodontal disease~~ ______

mu ne response in T hl cell development following Leish-

mania major infection. J Leukoc Biol 1995: 57: 515-522.

271. Schen del D, Gansb acher B. Tumor-specific lysis of h u m a n

renal cell carcinomas by tumo r-infiltrating lymphocytes:

mo dulatio n of recognition throu gh retroviral transd uction

of tumour cells with interleukin 2 complementary DNA

and exogenous alpha interferon treatment. Cancer Res1993: 53: 40204025.

272. Schenk K. IgG, IgA and IgM serum antibodies against

lipopolysaccharide from Bacteroides gingivalis in peri-

odo nta l hea lth a nd disease. J Period ont Res 1985: 20: 368-

377.

273. Schenk K, Michaelsen TE. IgG subclass distribution ofserum antibodies against lipopolysaccharide from Bacter-

oidesgingivalis in periodo ntal health an d disease. APMIS

1987: 95: 41-46.

274. Schre iber S, Heinig T, Thiele HG, Raedler A. Immunoregu-

latory role of interleukin 10 in pati ents with inflammatory

bowel disease. Gastroe nterolog y 1995: 1 0 8 1434-1444.

275. Schroede r HE. Transmigration a nd infiltration of leuko-

cytes in human junctional epithelium. Acta OdontolScand 1973: 17: 6.

276. Scott €? Selective differen tiation of CD 4+ T helper cell

subsets. Curr Opin Immunol 1993: 5: 391-397.

277. Scott I: Kaufrnann SHE. The role of T-cell subsets and

cytokines in the regulation of infection. Immunol Today

1991: 12: 346-348.

278. Seibert K, a n g Y Lea hy K Hauser S, Masferrer J, Perkins

W, Lee L, Isakson I Pharmacological and biochemical

demonstration of the role of cyclooxygenase 2 in in-

flammation and pain. Proc Natl Acad Sci U S A 1994: 91:

279. Seymour GJ. Possible mech anism s involved in t he immu-

noregulation of chronic inflammatory periodontal dis-

ease. J Dent Res 1987: 66: 2-9.280. Seymour GJ. Imp ortanc e of the host response in the peri-

odontium. J Clin Periodontol 1991: 18: 421-426.

281. Seymour GJ, Cole KL, Powell RN, Lewins E, Cripps AW,

Clancy RL. Interleukin-2 production and bone resorption

activity by unstimulated lymphocytes extracted from

chronically inflamed human periodontal tissues. Arch

Oral Biol 1985: 30 481-484.

282. Seymour GJ, Gemmell E, Reinhardt RA, Eastcott J, Taub-

m a n MA. Immunopathogenes isof chronic inflammatory

periodontal disease: cellular and m olecular mechanisms.

J Periodont Res 1993: 28: 478-486.

283. Shapira L, Soskolne A, Sela M, Offenbacher S, Barak V.

The secretion of PGE2, IL-la, IL-6, and TN Fa by adhe rent

mononuclear cells from early onset periodontitis pa-tients. J Periodontol 1994: 65: 139-146.

284. Shapira L, Soskolne W, Van Dyke T. Prostag landin E2 sec-

retion, cell maturation, and CD14 expression by mono-

cyte-derived macrophages from localized juvenile peri-

odontitis patients. J Periodontol 1996: 67: 224-228.

285. Sher A, Fiorentino D, Casper P, Pearce E, Mosma nn T. Pro-duction of IL-10 by CD 4+ T lymphocytes correlates with

down-regulation of Thl cytokine synthesis in helminth

infection. J Im mu nol 1991: 147: 2713-2716.

286. She r A, Gazz inelli RT, Osw ald II? Clerici M, Kullberg M,

Pearce EJ, Berzofsky JA, Mosmann TR, James SL Morse

HC, Shearer GM. Role of T-cell derived cytokines in the

downregulation of imm une responses in parasitic and re-

troviral infection. Immunol Rev 1992: 127: 181-204.

12013-12017.

287. Simmons D, Levy D, Yannoni Y Erikson R. Identification

of a phorbol ester-repressible v-src-inducible gene. Proc

Natl Acad Sci U S A 1989: 86 11778-11782.

288. Slots I, Genco RJ. Black-pigmented Bucteroides species,

Capnocytophagaspecies, and Act ino hill us actinornyce-

temcornitans in human periodontal disease: virulence

factors in colonization survival and tissue destruction. JDe nt Res 1984: 63: 412421.

289. Smith WL,Meade EA DeWitt DL. Interactions of PGH

synthase isozymes-1 and -2 with NSAIDs. Ann N Y Acad

Sci 1994: 744: 50-57.290. Snap per CM, Paul WE. Interferon-y a nd B cell stimulatory

factor-1 reciprocally regulate Ig isotype production.

Science 1987:236 944-947.

291. Spits H, Yssel H, Takebe Y Arai N, Yokota T, Lee F Arai

K, Banchereau J, De Vries J. Recombinant interleukin 4

promotes the growth of hum an T cells. J Immunol 1987:

292. Stashenko I:Dewhirst FE, PerosW ent RL, Ago JM. Syn-

ergistic interactions between interleukin 1, tumor ne-

crosis factor, and lymphotoxin in bone resorption. Im-munol 1987: 138: 1464-1468.

293. Stashenko I:Fujiyoshie I:Obemesser MS, Prostak L, Haf-

fajee AD, Socransky SS. Levels of interleukin 1 beta in

tissue from sites of active periodontal disease. J Clin Peri-

odontol 1991: 1 8 548-554.

294. Stein SH, Hendrix CL. Interleukin-10 pro mote s anti-co lla-

gen antibody production in gingival mononuclear cells. J

Dent Res 199 6 75: 158 (abstr 1122).

295. Street NE, M osma nn TR. Functional diversity of T

lymphocytes due to secretion of different cytokine pat-

terns. FASEB 1 1991: 5: 171-177.

296. Suzuki JB, Risom L, Falkler WA Jr, Collison C, Bowers G.

Effect of periodontal therapy on spontaneous lymphocyte

response and neutrophil chemotaxis in localized an d gen-eralized juvenile periodontitis patients. 1Clin Periodontol

1985 12: 124-134.

297. Sym ons JA, Young PR, DuffGW. Soluble type U interleukin

1 (IL-1) receptor bin ds a nd blocks p rocessing of IL-1 beta

precursor an d loses affinity for IL-1 receptor antagonist.

Proc Natl Acad Sci U S A 1995: 92: 1714-1718.

298. Takahashi K, Takashiba S Nagai A, Takigawa M, Myoukai

E Kurihara H, Murayama Y.Assessment of interleukin-6

in the pathogenesis of periodontal disease. 1 Periodontol

299. Takeichi 0, Taubman MA, Haber J, Smith DJ, Moro I.

Cytokine profiles of CD4 and CD8 T cells isolated from

adult periodontitis gingivae. J Dent Res 1994: 73: 205

(abstr 1549).300. Takigawa M, Takashiba S, Takahashi K, Arai H, Kurihara

H, Murayama Y. Prostaglandin E2 inhibits interleukin-6

release but not transcription in human gingival fibro-

blasts stimulated wth interleukin-lp or tumor necrosis

factor-a. J Period ontol 1994: 65: 1122-1127.

301. Tanaka K, Aikawa Y, Kawasaki H. Asaoka K, Inaba T,Yoshida C. Pharmacological studies on 3-formylamino-

7 -methylsulfonylamino- 6-phenoxy-4H 1 benzopyran-4 -on e (T-6141, a novel antiinflammatory agent. 4th com-

munication: inhibitory effect on the production of in-

terleukin-1 and interleukin-6. J Pharmacobiodyn 1992:

15: 649-655.

302. Tanaka K, Makino S, Shimotori T, Aikawa Y, Inaba T, Yosh-

ida C. Pharmacological studies of the new antiinflamma-

139: 1142-1 147.

1994: 65: 147-153.

141



Gemmell et al

tory agent 3-formylamino-7-methyIsulfonylamino-6-

phenoxy-4'-l-benzopyran-4-one:ffect on the arachidon-

ic acid cascades. Arzneimittelforschung 1992: 42: 945-950.

303. Taubman MA, Stoufi ED, Ebersole IL Smith DI. Pheno-

typic studies of cells from periodontal disease tissue. l

Periodont Res 1984: 19: 587-590.

304. Tepper RI, Coffman RL, Leder F A n eosinophil-dependent

305.

306.

307.

308.

309.

310.

311.

312.

313.

314.

315.

316.

317.

318.

319.

.mechanism for the antitumour effect of interleukin-4.

Science 1992: 257: 548-551.

Te Velde AA, Huijbens RJ, Heije K de Vries JE , Figdor CG.

Interleukin-4 (IL-4) inhibits secretion of IL- 1 beta, tumor

necrosis factor alpha, and 1L-6 by human monocytes.

Tew JG, Engel D, Mangan D. Polyclonal B-cell activation

in periodontitis. 1 Periodont Res 1989: 24: 225-241.

Thomson BN, Mundy GR, Chambers TI. Tumor necrosis

factors alpha and beta induce osteoblastic bone resorp-

tion. J Immunol 1987: 138: 775-779.

Tokoro Y Yamamoto T, Hara K. IL-ls mRNA as the pre-

dominant inflammatory cytokine transcript: correlation

with inflammatory cell infiltration into human gingiva. IOral Pathol Med 1996: 25: 225-231.

Tonetti MS, Freiburghaus K. Lang NE Bickel M. Detection

of IL-8 and matrix metalloproteinase transcripts in

healthy and diseased gingival biopsies by RNAIPCR. J

Periodont Res 1993: 28: 511-513.

Tonetti MS, lmboden MA, Gerber L, Lang N E Laissue 1

Mueller C. Localized expression of mRNA for phagocyte-

specific chemotactic cytokines in human periodontal in-

fections. Infect Immun 1994: 62: 4005-4014.

Trinchieri G. Interleukin-12 an d its role in the generation

of Thl cells. Immunol Today 1993: 14: 335-337.

Trinchieri G, Perussia B. Immune interferon: a pleiotropic

lymphokine with multiple effects. Immunol Today 1985:

Van Dyke TE, Bartholomew E, Genco RJ, Slots J Levine

MJ. Inhibition of neutrophil chernotaxis by soluble bac-

terial factors. 1 Periodontol 1982: 53: 502-508.

Van Dyke TE, Lester MA, Shapira L. The role of the host

response in periodontal disease progression: implications

for future treatment strategies. I Periodontol 1993:

64(suppl): 792-806.

Vane J Bottling R. Mechanism of action of anti-inflam-

matory drugs. Scand J Rheumatol 1996: 25(suppl 102): 9-

21.

Vogel R Schneider L, Goteiner D. The effects of a topi-

cally-active non-steroidal anti-inflammatory drug on liga-

ture-induced periodontal disease in the squirrel monkey.

J Clin Periodontol 1986: 13: 139-144.Wagner E, Cotten M, Foisner R, Birnstiel M. Transferrin-

polycation-DNA complexes: the effect of poly-cations on

the structure of the complex and DNA delivery to cells.

Proc Natl Acad Sci U S A 1991: 88: 4255-4259.

Wallner BE Mattaliano R J Hession C, Cate RL,Tizard R

Sinclair LK Foeller C, Chow EB Browning JL, Ramachand-

ran KL, Pepinsky RB. Cloning and expression of human

lipocortin, a phospholipase A2 inhibitor with potent anti-

inflammatory activity. Nature 1986: 320: 77-81.

Walsh LJ, Stritzel E Yamazaki K, Bud PS, Gemmell E,

Seymour GI. Interleukin-1 and interleukin-1 inhibitor

production by human adherent cells stimulated with

periodontopathic bacteria. Arch Oral Biol 1989: 34: 679-

683.

Blood 1990: 76: 1392-1397.

6: 131-136.

320. Wendling D, Racadot E, Wijdenes I. Treatment of severe

321.

322.

323.

324.

325.

326.

327.

328.

329.

330

331

332.

333.

334.

335.

rheumatoid arthri tis by anti-interleukin 6 monoclonal

antibody. J Rheumatol 19 93 2 0 259-262.

Whitney C, Ant J, Moncla B, Johnson B, Page RC, Engel

D. Serum immunoglobulin G antibody to Porphyromonus

gingivulis in rapidly progressive periodontitis: titer, avid-

ity, and subclass distribution. Infect Immun 1992: 60:

Wdiams R, Jeffcoat M, Howell T, Rolla A, Stubbs, Teoh

K, Reddy M , Goldhaber l? Altering the progression of

human alveolar bone loss with the non-steroidal anti-

inflammatory drug flurbiprofen. J Periodontol 1989: 60:

485-490.

Williams TJ, Peck MJ. Role of prostaglandin-mediated

vasodilation in inflammation. Nature 1977: 270: 530-532.

Wills D, Maneval E Menzel M, Harris ME Sutjipto S, Vail-

lancourt MT. Huang WM, Johnson DE, Anderson SC, Wen

SE Bookstein R, Shapard H, Gregory R.Development and

characterization of recombinant adenovirus encoding hu -

man p53 for gene therapy of cancer. Hum Gene Ther

1994: 5: 1079-1088.Wilson M, Kamin S, Harvey W Bone resorbing activity of

purified capsular material from Actinobucillus actino-

mycetemcomitans. J Periodont Res 1985: 20: 484491.

Winning T, Gemmell E, Polak B, Savage NW, Walsh LW,

Seymour GI. Expression of CDla on monocytes cultured

with supernatants from periodontally diseased gingival

epithelial cells. Oral Dis 1996 2: 247-252.

WOW1 Malone R Williams P, Chong W, Acsadi G, Jani A,

Felgner PL. Direct gene transfer into mouse muscle in

vivo. Science 1990: 247: 1465-1468.

Xu Amano J, Aicher WK, TaguchiT Kiyono H, McGhee JR .

Selective induction of Th2 cells in murine Peyer's patches

by oral immunisation. Int Immunol 1992: 4 433-445.

Xu Amano I, Kiyono H, Jackson RJ, Staats HE Fujihashi KBurrows PD, Elson CO, Pillai S, McGhee JR. Helper T cell

subsets for immunoglobulin A responses: oral immunis-

ation with tetanus toxoid and cholera toxin as adjuvant

selectively induces Th2 cells in mucosa associated tissues.

1 Exp Med 1993: 178: 1309-1320.

Yamamoto M, Fujihashi K, Hiroi T,McGhee JR, Van Dyke

TE, Kiyono H . Molecular and cellular mechanisms for

periodontal diseases: role of Thl and Th2 type cytokines

in induction of mucosal inflammation. 1 Periodont Res

Yamashita K , Eastcott JW aubman MA, Smith DI, Cox

DS. Effect of adoptive transfer of cloned Actinobucillus

uctinomycetemcorniturisspecificT helper cells on peri-

odontal disease. Infect Immun 1991: 59: 1529-1534.Yamazaki K Nakajima T, AoyagiT,Hara K. Immunohistol-

ogical analysis of memory T lymphocytes an d activated B

lymphocytes in tissues with periodontal disease. J Peri-

odont Res 1994: 28: 324-334.

Yamazaki K, Nakajima T, Hara K . Immunohistological

analysis of T cell functional subsets in chronic inflamma-

tory periodontal disease. Clin Exp Immunol 1995: 99:

384-39 1.

Yamazaki K, Polak B. Bird PS, Gemmell E, Hara K,

Seymour GI. Effects of periodontopathic bacteria on IL-

1 and IL-I inhibitor production by human polymorpho-

nuclear neutrophils. Oral Microbiol Immunol 1989: 4:

Yavuzyilmaz E, Yamalik N , Bulut S, Ozen S, Ersoy E Saatqi

2194-2200.

1997: 32: 115-119.

193-198.

142




genase-2 mRNA in human gingival fibroblasts. Inflam-

mation 1995: 19: 549-560.

337. Zurawski G, de Vries JE. Interleukin 13, an interleukin 4-

like cytokine that acts on monocytes and B cells, but not

on T cells. Immunol Today 1994: 15: 19-26.

0.The gingival crevicular fluid interleukin-lp and tumour

necrosis factor-a levels in patients with rapidly progress-

ive periodontitis.Aus Dent J 1995:40: 46-49.

336. Yucel-Lindberg T, Ahola H, Nilsson S , Carlstedt-DukeJ

Modeer T. Interleukin-10 induces expressionof cyclooxy-

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Cytokines and Prostaglandins in Immune Homeostasis and Tissue Destruction in Periodontal Disease