Innate immunity includes which of the following components?

• A. Antibodies
• B. B cells
• C. Macrophages
• D. T cells

Answer: (C)

Innate immunity is made up of rapid, non-specific defense mechanisms. Macrophages fit this role because they reside in tissues, patrol for microbes, and kill them by phagocytosis while releasing inflammatory signals to recruit other immune cells. They recognize pathogens through pattern recognition receptors that detect common microbial features rather than specific antigens. In contrast, antibodies and B/T cells belong to the adaptive immune system, which relies on antigen-specific receptors and builds memory. Macrophages can also present antigen to helper T cells to help activate the adaptive response, but their primary function is within innate defense.