Which of the following is produced by antigen-stimulated T cells?

• A. Humoral response
• B. Cytokines
• C. Plasma cells
• D. Antibody

Answer: (B)

When T cells are activated by an antigen, they release cytokines—small signaling molecules that coordinate and amplify the immune response. These cytokines act on other immune cells to promote proliferation, differentiation, and activation; for example, IL-2 drives T cell growth, IFN-γ activates macrophages, and various cytokines help B cells mature and undergo class switching. This signaling is the direct product of antigen-stimulated T cells, making cytokines the best answer.

Humoral response and antibodies come from B cells. B cells differentiate into plasma cells, which are the factories that secrete antibodies. So the antibody itself and the plasma cells that produce it are not direct products of T cells, even though T cells can influence and help drive the humoral response through cytokine signaling.