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T-CELL MEMORY
Central
Effector
1781: Measles epidemic in the Faroe Islands
No measles for 65 years
1846: Measles epidemic
Those individuals, who were older than 65 years and were infected in 1781 did not became sick, but some elderly people got the infection
1. Life-long protection can be induced against some viruses
2. Presence of the virus is not needed for the maintenance of immunological memeory
Immunological memory
Inhabitants: 46 000Area: 1400 km2
DEVELOPMENT OF CELLULAR MEMORYNegative regulation of the immune system
Days5 10 15 20 25 30
Naive lymphocytes
Az antigen-specific cell number
Primary effector cells
Secunder effector cells
Memory
DIFFERENTIATION
AICD
EXPANSION
AICD
MEMORY
Days
Activation Induced Cell Death
Presence of specific antibodies during primary and secondary immune responses protects against repeated infections
• A successful primary immune response eliminates the pathogen and results in long-lasting immunological memory• Antibodies produced during the primary immune response protect against re-infection by neutralization and opsonization.
Both effector B and T cells and memory B and T cells are produced during a primary immune response
Comparison of the B-cell populations that participate in the primary and secondary adaptive immune responses
The amount and affinity of antibody increase after successive immunizations with the same antigen
IgG antibody suppresses the activation of naive B cells by cross-linking the B-cell receptor and FcγRIIB1
on the B-cell surface
Passive immunization with anti-Rhesus antigen IgG prevents hemolytic anemia of the newborn
Highly mutable viruses such as influenza gradually escape from immunological memory without stimulating
a compensatory immune response
Memory CD4 T cells express an altered CD45 isoform that works more effectively with the T-cell receptor
and co-receptors
Naive T Effector T
Cytokines/cytotoxicity
AICD
Central memory T
Effector T
Cytokines/cytotoxicity
PERIPHERAL LYMPHOID ORGANS
PERIPHERAL TISSUESSkin dermis, gut lamina propria,
alveolar space
Tissue-specific migration
Effector memory T
Effector T
Cytokines/cytotoxicity
ANTIGEN/ SITE OF INFLAMMATION
T-cells differentiate into central and effector memory cells
AGE
THYMUS PERIPHERY
N
A
I
V
E
IMMUNOLOGICAL EXPERIENCEIMMUNOLOGICAL EXPERIENCE
M
E
M
O
R
Y
Resting Activated Resting Activated
Tissue effector memory T cells Lymphoid central memory T cells
PRODUCTION OF EFFECTOR
MOLECULES
CYTOTOXIC MEMORY T LYMPHOCYTESCYTOTOXIC MEMORY T LYMPHOCYTES
Proliferation
Cytotoxicity
DEPENDENCE OF ANTIGEN IN THE MAINTENANCE OF MEMORY T LYMPHOCYTES IN AIRWAYS
MONTHS AFTER INFECTIONMONTHS AFTER INFECTION
11 33 66
After successful elimination of viral infections the number of antigen presenting DC and the newly activated memory T cells is decreased
Secondary antigen-specific effector T cells developing from effector memory (TEM ) cells
LYMPH NODE
Memory T cells
Antigen-specific
Non antigen-specific24 – 72 hrs
Secondary antigen-specific effector T cells developing from
central memory (TCM ) cells
Woodland DL & Kohlmeier JR 2009 Nat Rev 9:153