Written by the Fiveable Content Team • Last updated August 2025
Written by the Fiveable Content Team • Last updated August 2025
Definition
Cell-mediated immune response is a form of adaptive immunity where T cells respond to infected or abnormal cells. It is crucial for eliminating pathogens that reside within host cells and for tumor surveillance.
T cells, especially cytotoxic T lymphocytes (CTLs), play a central role in cell-mediated immune response.
Helper T cells (Th1) release cytokines that activate other immune cells like macrophages.
Cell-mediated immunity does not involve antibodies but relies on direct cellular attack.
Major Histocompatibility Complex (MHC) class I molecules present antigens to cytotoxic T cells.
Memory T cells are generated during the cell-mediated immune response, providing long-term immunity.
Related terms
Cytotoxic T Cells: A type of T cell that directly kills infected or cancerous cells by inducing apoptosis.
Helper T Cells: A type of T cell that assists other white blood cells in immunologic processes, including activating and directing other immune responses.
Major Histocompatibility Complex (MHC): Molecules on cell surfaces that present antigen fragments to T cells, triggering an immune response.