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Flashcards in Module 7: Type III Deck (5)
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Type III also called

Immune Complex mediated hypersensitivity


Antigen/antibodies involved in Type III are

Floating around in plasma
Not attached to cells or tissue

If Ag and Ab persist, they may precipitate or deposit in tissues as an immune complex


Disposition of Ag-Ab complexes depend on (2)

an increase in vascular permeability
Increased blood pressure and turbulence


Complete set of steps for Type III

1. Soluble antigen and Ab combine
2. Bind complement and stimulate PLT aggregation
3. Amines released from PLT aggregation cause endothelial cell retraction
4. Immune complex is deposited into blood vessel wall (where it is retracted)
5. PLT aggregation and complement activation
6. Microthrombi form on basement membrane
7. Neutrophils attracted to the site cannot ingest the complexes
8. Neutrophils release their enzymes leading to tissue damage


6 examples of Immune complex disorders

Serum Sickness
Complications in Renal transplants
Arthur Reaction (vasculitis at injection site of injection of an antigen)