Which immune system cells secrete antibodies?

• A. B Cells
• B. T Cells
• C. Plasma Cells
• D. Macrophages

Answer: (C)

Antibodies are produced by plasma cells, which are differentiated B cells. When a B cell encounters its specific antigen and receives help from other immune cells, it can mature into a plasma cell that acts as a factory, secreting large amounts of a single type of antibody into the blood and tissues. T cells help coordinate the response but do not produce antibodies themselves. Macrophages are phagocytes that ingest pathogens and present antigens rather than secreting antibodies. So the cells that secrete antibodies are plasma cells.