What is the primary role of helper T cells in the immune response?

• A. They directly kill infected cells.
• B. They phagocytose pathogens.
• C. They activate and regulate other immune cells by releasing cytokines.
• D. They produce antibodies.

Answer: (C)

Helper T cells coordinate the immune response by releasing signaling molecules called cytokines that activate and regulate other immune cells. When an antigen is presented on MHC class II molecules by an antigen-presenting cell, helper T cells become activated and secrete cytokines such as IL-2, IFN-γ, and IL-4. These signals stimulate B cells to proliferate and differentiate into antibody-secreting plasma cells, promote the activation and expansion of cytotoxic T cells, and enhance macrophage phagocytic activity. In short, they don’t directly kill infected cells, nor do they phagocytose pathogens or produce antibodies themselves; instead, they orchestrate the immune response, making it more effective. Loss or dysfunction of helper T cells impairs both humoral and cellular immunity, underscoring their central coordinating role.