Imunitas pada kulit

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)

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Components of the immune system

Innate immune system

Response is non-

specificExposure leads to

immediate maximal response

Cell-mediated and humoral components

No immunological memory

Found in nearly all forms of life (plants & animals)

Adaptive immune system

Pathogen and antigen specific response

Lag time between exposure and maximal response

Cell-mediated and humoral components

Exposure leads to immunologic memory

Found only in vertebrates

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

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The immune system protects organisms with layered defenses of increasing specificity

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– Innate immune systems are found in all plants and animals

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.) Various stimuli

mediator release– Immunologic: IgE

binding antigen– Nonimmunologic: Physical,

drugs, complement

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

– Cell surface molecules: CD1a, MHC II, ATPase, Fc receptor for IgG, C3 receptor, B7, several CAMs

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