B Cells and Plasma Cells are part of the __________-Mediated Immune Response.

• A. Macrophage
• B. Antigen
• C. Antibody
• D. Auto

Answer: (C)

Antibody-mediated immune response is driven by B cells and their product antibodies. B cells mature in the bone marrow and, when they encounter a specific antigen, they differentiate into plasma cells that secrete large amounts of antibodies. These antibodies circulate in body fluids, bind to the antigen, and neutralize pathogens, tag them for destruction by other immune cells, or activate complement. This is why B cells and plasma cells characterize the antibody-mediated (humoral) arm of immunity.

Macrophages are phagocytes that clear pathogens and can present antigens, but they’re not the mediator of the antibody-based response. An antigen is the substance that triggers the immune response, not the mediator itself. Auto refers to self-reactivity and autoimmunity, not the antibody-driven process described here.