Which cells are most directly responsible for producing antibodies after activation?

• A. B cells
• B. T cells
• C. Neutrophils
• D. Plasma cells

Answer: (D)

Antibody production after activation is carried out by plasma cells. When a B cell encounters its specific antigen and receives help from a T helper cell, it differentiates into plasma cells. These cells are specialized to synthesize and secrete large amounts of antibodies into blood and lymph, providing targeted humoral defense. Some activated B cells become memory B cells for faster responses upon re-exposure, but memory cells do not actively produce antibodies right away. T cells help activate B cells and guide their differentiation, but they themselves do not secrete antibodies. Neutrophils are innate immune cells focused on phagocytosis and do not produce antibodies either.