Hypersensitivity - Lecture

Question 1

name the 4 types

Answer 1

1) IgE-mediated mast cell degranulation (“atopic”/allergen responses)
2) Cytotoxic Abs against cell surface antigens
3) Immune complex mediated
4) Delayed-Type (T cell mediated)

Question 2

how does Type I occur?

Answer 2

Mast cells have the FCeRI receptor on surface (high affinity to IgE). A harmless allergen can bind, cross-linking the IgEs and triggering degranulation.

Question 3

how does Type II occur?

Answer 3

Abs recognize, bind antigens. ADCC triggered (anything with a FC receptor, ability to make cytokines) or Abs may directly attack

Question 4

how does Type III occur?

Answer 4

immune complexes get trapped => activate Mphages, complement, neutrophils