Which statement best describes the role of macrophages in immunity?

• A. Macrophages phagocytose pathogens.
• B. Macrophages produce antibodies.
• C. Macrophages differentiate into B cells.
• D. Macrophages are only in the nervous system.

Answer: (B)

Macrophages are frontline phagocytes that engulf and digest invading microbes, helping to clear pathogens from the body. After digesting a microbe, they also present its fragments on their surface to helper T cells, linking innate and adaptive immunity. They release cytokines that recruit and activate other immune cells, coordinating the immune response. Antibody production, by contrast, is carried out by B cells (and plasma cells), not macrophages. Macrophages are found throughout the body in many tissues, not just in the nervous system. Because phagocytosis of pathogens best captures their primary role, that statement is the most accurate description of macrophages in immunity.