Question

Which of the following cell releases a hydrolytic enzyme during type IV hypersensitivity reaction?

• A. Macrophages
• B. T killer cells
• C. T helper cells
• D. All of the above

Answer 1

The correct option is A Macrophages

Type IV hypersensitivity Is a type of cell-mediated response. CD4+ helper T cells recognize antigen in a complex with major histocompatibility complex Class II. The antigen-presenting cells are macrophages that secrete IL-12, which stimulates the proliferation of further CD4+ Th cells which secrete IL-2 and interferon gamma. This further inducing the release of other Th cytokines, thus mediating the immune response. Activated CD8+ T cells kill target cells on contact, whereas activated macrophages produce hydrolytic enzymes. Thus the correct answer is option A.