Which of the following describes a function of T helper cells?

• A. Secretes B cell growth factor
• B. Destroys virus-infected cells
• C. Suppresses T cell and B cell activity
• D. Phagocytosis of pathogens

Answer: (A)

T helper cells coordinate the immune response by signaling other immune cells. They release cytokines that stimulate B cell activation, proliferation, and differentiation into antibody-secreting plasma cells, effectively providing signals that promote B cell growth. This explains why describing their role as secreting B cell growth factor is the best match. They do not directly kill virus-infected cells (that task belongs to cytotoxic T cells), they do not suppress T and B cell activity (that is a role of regulatory T cells), and they do not perform phagocytosis (a function of phagocytes like macrophages and neutrophils).