Which cells are specialized for cell-mediated immunity?

Which cells are specialized for cell-mediated immunity?

• A. B cells
• B. Plasma cells
• C. CD-8 T cells
• D. Helper T cells

Answer: (C)

CD-8 T cells are primarily responsible for cell-mediated immunity, as they directly attack and destroy infected cells, tumor cells, and foreign cells. This subset of T cells recognizes antigens presented by major histocompatibility complex (MHC) class I molecules, which are found on all nucleated cells. Once activated, CD-8 T cells can proliferate and differentiate into cytotoxic T lymphocytes (CTLs) that execute their function by releasing perforins and granzymes to induce apoptosis in target cells.

While B cells and plasma cells play crucial roles in humoral immunity by producing antibodies, they do not engage directly in the destruction of infected or abnormal cells. Helper T cells, although vital in orchestrating the immune response and assisting other immune cells, do not directly attack cells. Their role is to activate B cells and other T cells, forming a network of immune support rather than directly mediating cellular attacks. Therefore, CD-8 T cells are specifically tailored for cell-mediated immune responses, positioning them as the correct answer.