Imunitas pada kulit

dr. Rohmania Setiarini

Pathogens(such as bacteria,fungi, and viruses)

INNATE IMMUNITY(all animals)

• Rapid response

Recognition of traits sharedby broad ranges ofpathogens, using a smallset of receptors

•

Recognition of traits specific to particularpathogens, using a vastarray of receptors

•

• Slower response

Barrier defenses:SkinMucous membranesSecretions

Internal defenses:Phagocytic cellsNatural killer cellsAntimicrobial proteinsInflammatory response

Humoral response:Antibodies defend againstinfection in body fluids.

Cell-mediated response:Cytotoxic cells defendagainst infection in body cells.

ADAPTIVE IMMUNITY(vertebrates only)

Immunity Innate & Adaptive

First line of defense

NonspecificRapid onsetNo protective

immunityNo memoryPhagocyte-

mediated

ActivatedVery specificSlowerProtective

immunity possible

Memory possible

Lymphocyte- mediated

Interval between exposures

First exposure

Second exposure

Time

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Section 40-2Immune Responses

Roles of the Skin

• The skin or integumentary system has four roles◦ It acts as a barrier against infection and injury◦ It helps to regulate body temperature◦ It removes waste products from the body◦ Provides protection against UV radiation from the

sun• It also serves as a way through which sensations

are transmitted to the nervous system

7

The immune system protects organisms

Most simply, 1. physical barriers prevent pathogens such as bacteria and viruses from entering the body

If a pathogen breaches these barriers, the 2. innate immune system provides an immediate, but non-specific response

If pathogens successfully evade the innate response, vertebrates possess a third layer of protection, the 3. adaptive immune system– Here, the immune system adapts its response during an infection to

improve its recognition of the pathogen– This improved response is then retained after the pathogen has been

eliminated, in the form of an immunological memory, and allows the adaptive immune system to mount faster and stronger attacks each time this pathogen is encountered

Innate Immune Features of the Skin

Cells– Phagocytes: Macrophages, neutrophils, NK

cells– Mast cells

Circulating chemicals– Complement

Locally produced chemicals– Cytokines, histamine

Mast Cells Bone marrow-derived Dermal resident Perivascular Mediators

– Preformed (histamine, e.g.)– Newly synthesized (cytokines,

e.g.)

Cells of the Cutaneous Adaptive Immune Response

Langerhans’ cell Dermal dendrocytes Keratinocytes T-cells Endothelial cells

Langerhans’ Cells

Bone marrow-derived– Monocyte lineage

Transient epidermal cells Dendritic cell Electron microscopy: Birbeck granules,

convoluted nucleus

Langerhans’ Cells:Epidermal Transients

Migration and maturationBone marrow Blood Epidermis (LC)

Afferent lymph Lymph node Functions– Antigen capture and processing– Presentation of antigen– Costimulation of naïve T-cells– Produce activating cytokines

Langerhans’ Cell Migration

Antigen

Keratinocytes As Immune Cells

Old view: Keratinocytes... Are passive barrier cells Are passive victims of immune attack

Keratinocytes As Immune Cells

Newer view: Keratinocytes... Produce cytokines

– e.g., IL-1, TNF-, Chemokines Respond to cytokines

– e.g., IFN, IL-1 Upregulate ICAM-1 Present antigen Antimicrobial peptide

Endothelial Cells &Cutaneous Inflammation

Increase permeability When activated, endothelial cells...

– cell surface expression of P-selectin for enhanced leukocyte margination

– synthesis & expression of E-selectin for selective T-cell (CLA +) homing to the skin

– expression of VCAM-1 & ICAM-1 to stop leukocytes and allow diapedesis

Immune response amplified

Cutaneous Lymphocyte Antigen (CLA)

Specific skin homing marker on T-cells CLA+ lymphocytes are memory/effector cells

(CD45RO +) Cell adhesion to endothelial cell

– E-selectin is ligand With cutaneous inflammation, E-selectin up-

regulated, CLA+ cells selected

The Skin Immune System

Components1. APCs: Langerhans cells, dermal

dendrocytes, dermal macrophages2. Keratinocytes3. Endothelial cells4. Skin-homing T-cells5. Draining regional lymph vessels and nodes

Immune-response elements in non-inflamed skin.

Innate immune mechanisms in the skin

Adaptive immune responses in the skin

Immune-surveillance mechanisms in the skin