Type 4 Hypersensitivity

Question 1

Type 4

Answer 1

Cell Mediated (Not antibody)
Prolonged onset (24-48 hours)

Question 2

What happens during sensitisation phase?

Answer 2

Antigen specific T lymphoyctes (T-helper 1) are generated

Question 3

What happens during re-exposure?

Answer 3

○ Leads to antigen presentation and reactivation of sensitised T-helper 1 cells
○ Travel of site of presentation
○ Release (Interferon gamma) IFγ and chemokines
○ Recruitment of mononuclear inflammatory cells
Macrophages
CD4+ (T helper)
CD8+ (Cytotoxic)
Granulocytes
○ Further proinflammatory cytokines are released from infiltrating cells

Question 4

Examples of type 4

Answer 4

TB testing in cattle
* Cutaneous delayed type hypersensitivity reaction

Question 5

Treatment for Type 4 hypersensitivity

Answer 5

Eliminate cause
Provide anti-inflammatory therapy
Provide immunosuppressive therapy