What type of white blood cell develops from B lymphocytes and produces antibodies?

• A. T lymphocytes
• B. Monocytes
• C. Plasma cells
• D. B lymphocytes

Answer: (C)

Antibody production is carried out by plasma cells, the specialized descendants of B lymphocytes. When a B cell encounters its specific antigen and receives help from helper T cells, it can differentiate into plasma cells. These cells are filled with rough endoplasmic reticulum to produce large amounts of antibodies (immunoglobulins), which are secreted into the blood to recognize and neutralize pathogens or mark them for attack by other parts of the immune system. Some B cells become memory B cells for quicker responses in the future, but the actual antibody factories are plasma cells. Other listed cells have different roles—T lymphocytes coordinate and execute cellular responses without producing antibodies, and monocytes become macrophages or dendritic cells—so plasma cells best fit the description.