Imunitas kulit

8/13/2019 Imunitas kulit

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Imunitas pada kulit


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Pathogens(such as bacteria,fungi, and viruses)

INNATE IMMUNITY(all animals)

Rapid response

Recognition of traits sharedby broad ranges ofpathogens, using a small

set of receptors

Recognition of traitsspecific to particularpathogens, using a vastarray of receptors

Slower response

Barrier defenses:SkinMucous membranesSecretionsInternal 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)


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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 aretransmitted to the nervous system


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The immune system protects organisms with layereddefenses of increasing specificity

Most simply, 1. physical barriers prevent pathogens such as bacteria and viruses from entering the bodyIf a pathogen breaches these barriers, the 2. innate immunesystem provides an immediate, but non-specific response Innate immune systems are found in all plants and animalsIf pathogens successfully evade the innate response, vertebrates

possess a third layer of protection, the 3. adaptive immunesystem 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 beeneliminated, in the form of an immunological memory, and allows theadaptive immune system to mount faster and stronger attacks each time this

pathogen is encountered


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Innate Immune Features of the Skin

Cells Phagocytes: Macrophages, neutrophils, NK

cells Mast cells

Circulating chemicals Complement

Locally produced chemicals Cytokines, histamine


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Mast CellsBone marrow-derivedDermal residentPerivascularMediators Preformed (histamine, e.g.) Newly synthesized (cytokines,

e.g.)

Various stimulimediator release Immunologic: IgE binding antigen Nonimmunologic: Physical,

drugs, complement


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Cells of the Cutaneous Adaptive

Immune Response

Langerhans cell Dermal dendrocytesKeratinocytesT-cellsEndothelial cells


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Langerhans Cells

Bone marrow-derived Monocyte lineage

Transient epidermal cellsDendritic cell Cell surface molecules: CD1a, MHC II,

ATPase, Fc receptor for IgG, C3 receptor,

B7, several CAMsElectron microscopy: Birbeck granules,convoluted nucleus


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Langerhans Cells:

Epidermal TransientsMigration and maturationBone marrow Blood Epidermis (LC)

Afferent lymph Lymph nodeFunctions

Antigen capture and processing

Presentation of antigen Costimulation of nave T-cells Produce activating cytokines


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LangerhansCell Migration

Antigen


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Keratinocytes AsImmune Cells

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


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Keratinocytes AsImmune Cells

Newer view : Keratinocytes...

Produce cytokines e.g., IL-1, TNF- , Chemokines

Respond to cytokines

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

Antimicrobial peptide


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Endothelial Cells &

Cutaneous InflammationIncrease permeabilityWhen activated, endothelial cells... cell surface expression of P-selectin

for enhanced leukocyte margination synthesis & expression of E-selectin

for selective T-cell (CLA +) homing tothe skin

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

Immune response amplified


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Cutaneous Lymphocyte Antigen

(CLA)Specific skin homing marker on T-cellsCLA+ 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


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The Skin Immune System

Components1. APCs: Langerhans cells, dermal

dendrocytes, dermal macrophages2. Keratinocytes3. Endothelial cells

4. Skin-homing T-cells5. Draining regional lymph vessels and

nodes


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Imunitas kulit