What is the primary function of B-lymphocytes in the immune system?

What is the primary function of B-lymphocytes in the immune system?

• A. To produce antibodies that target specific pathogens and facilitate immune responses.
• B. To destroy infected cells directly.
• C. To present antigens to macrophages.
• D. To regulate the immune response via cytokines.

Answer: (D)

B-lymphocytes are the antibody-producing cells of the adaptive immune system. Their main role is to make antibodies that recognize specific pathogens. When B cells are activated, they differentiate into plasma cells that secrete large amounts of antibodies into blood and lymph. These antibodies bind to pathogens, neutralize them, and tag them for attack by other parts of the immune system—such as phagocytes and the complement system—helping to clear infections. This humoral function is the defining task of B cells. B cells can also present antigens to T cells and secrete cytokines to influence other immune cells, but these roles are supporting activities that complement the primary function of antibody production. Therefore, antibody production best captures what B-lymphocytes do.