Which immune cells are primarily responsible for phagocytosis?

• A. T cells
• B. B cells
• C. Neutrophils and macrophages
• D. Natural killer cells

Answer: (C)

Neutrophils and macrophages are the primary immune cells responsible for phagocytosis, a crucial process in the immune response. Phagocytosis is the mechanism by which these cells engulf and digest pathogens, cellular debris, and other foreign material, thereby helping to clear infections and promote healing.

Neutrophils are among the first responders during an immune response, rapidly migrating to sites of infection or inflammation where they can phagocytize bacteria and other harmful entities. Macrophages, which derive from monocytes, take on a more prominent role in cleanup and orchestrating the immune response. They can engulf a broader range of particles over a longer time frame, and their ability to present antigens to T cells helps bridge the innate and adaptive immune responses.

In contrast, T cells and B cells play distinct roles in adaptive immunity, with T cells primarily involved in cell-mediated responses and B cells responsible for antibody production. Natural killer cells, on the other hand, are important for targeting virus-infected or tumor cells but do not perform phagocytosis. Therefore, the recognition of neutrophils and macrophages as the main phagocytic cells highlights their essential roles in innate immunity and the body’s defense against infections.