Which cell produces antibodies?

• A. Hepatocyte
• B. Plasma cell
• C. Thymocyte
• D. T cell

Answer: (B)

Antibodies are produced by B lymphocytes that have differentiated into plasma cells. When a B cell encounters its specific antigen and receives help from a helper T cell, it becomes activated and differentiates into a plasma cell, which serves as the antibody factory. Plasma cells synthesize and secrete large amounts of immunoglobulins, supported by a lot of rough endoplasmic reticulum and Golgi apparatus to handle high-rate production. The other options don’t fit this role: hepatocytes in the liver produce various proteins but not antibodies; thymocytes are immature T cells in the thymus and do not secrete antibodies; mature T cells coordinate cellular immunity rather than producing antibodies.