The immune cells responsible for antibody production are which cells?

• A. T lymphocytes
• B. B lymphocytes (B cells)
• C. Macrophages
• D. Natural killer cells

Answer: (B)

Antibody production is carried out by B lymphocytes that differentiate into plasma cells. When a B cell encounters its specific antigen and receives help from helper T cells, it becomes activated and proliferates, turning into a plasma cell that secretes large amounts of antibody. These antibodies circulate in the blood and bind to the antigen, neutralizing pathogens and marking them for destruction by other immune cells. Memory B cells remain to provide a faster, stronger response if the same antigen is encountered again.

Other cells have different roles: T lymphocytes coordinate and carry out cellular immune responses but do not produce antibodies; macrophages ingest pathogens and present antigens to T cells; natural killer cells destroy infected or abnormal cells without producing antibodies.