Which type of immunity is produced by T cells that attack infected or abnormal body cells?

• A. Humoral immunity
• B. Cell-mediated immunity
• C. Innate immunity
• D. Passive immunity

Answer: (B)

T cells mediate a cellular immune response, where the attack is directed at infected or abnormal body cells rather than at free-floating pathogens. Cytotoxic T cells recognize specific antigens presented on the surface of infected or cancerous cells via MHC class I molecules, then release perforin and granzymes to induce the target cell’s apoptosis. This direct, cell-to-cell attack is the hallmark of cell-mediated immunity, which contrasts with humoral immunity that relies on B cells producing antibodies to neutralize pathogens in body fluids. Innate immunity refers to non-specific barriers and responses, and passive immunity involves transfer of antibodies from another individual. So, the type of immunity produced by T cells that attack infected or abnormal cells is cell-mediated immunity.