Which T cell subset releases IL-2 and IFN-γ, and what are the actions of these cytokines?

Which T cell subset releases IL-2 and IFN-γ, and what are the actions of these cytokines?

• A. Th1; IL-2 activates CD8+ T cells; IFN-γ activates macrophages and promotes IgG switching
• B. Th2; IL-4 activates B cells; IL-5 activates eosinophils
• C. Th17; IL-17 recruits neutrophils
• D. Treg; IL-10 suppresses inflammation

Answer: (A)

This question tests understanding of T helper cell subsets and their cytokines. Th1 cells release IL-2 and IFN-γ. IL-2 acts as a growth factor that drives proliferation of T cells, especially CD8+ cytotoxic T cells, helping them expand and develop their killing ability. IFN-γ activates macrophages, boosting their microbicidal functions, and it also nudges B cells toward producing IgG isotypes that are effective at opsonization and activating complement. Put together, these actions describe a Th1-driven, cell-mediated immune response aimed at intracellular pathogens. Other T helper subsets produce different cytokines—Th2 mainly drives humoral responses with IL-4, IL-5, and IL-13 (including eosinophil activation and certain IgG isotypes), Th17 recruits neutrophils via IL-17, and regulatory T cells dampen responses with IL-10 and TGF-β—so they don’t match the IL-2 and IFN-γ pattern.

This question tests understanding of T helper cell subsets and their cytokines. Th1 cells release IL-2 and IFN-γ. IL-2 acts as a growth factor that drives proliferation of T cells, especially CD8+ cytotoxic T cells, helping them expand and develop their killing ability. IFN-γ activates macrophages, boosting their microbicidal functions, and it also nudges B cells toward producing IgG isotypes that are effective at opsonization and activating complement. Put together, these actions describe a Th1-driven, cell-mediated immune response aimed at intracellular pathogens. Other T helper subsets produce different cytokines—Th2 mainly drives humoral responses with IL-4, IL-5, and IL-13 (including eosinophil activation and certain IgG isotypes), Th17 recruits neutrophils via IL-17, and regulatory T cells dampen responses with IL-10 and TGF-β—so they don’t match the IL-2 and IFN-γ pattern.