Cytotoxic CD8-positive T cell (CTL (for Cytotoxic T lymphocyte) or CD8+ T cell)

Cytotoxic CD8-positive T cells (commonly referred to as cytotoxic T lymphocytes or CTLs) are a subset of T lymphocytes that express the CD8 co-receptor and play a central role in immune-mediated destruction of infected or malignant cells[1][3]. These cells specifically recognize peptides presented by major histocompatibility complex class I (MHC-I) molecules on target cells and kill targets directly through release of cytolytic granules (perforin and granzymes) or via engagement of death receptors (Fas/FasL-mediated apoptosis). Recent findings show that CD8+ T cells can also mediate lysis of tumor cells lacking MHC-I through alternative mechanisms involving the NKG2D receptor and its ligands[2]. They are critical effectors in cancer immunotherapy, with their presence in the tumor microenvironment strongly correlated with favorable prognosis in many cancers. Therapies targeting their function include immune checkpoint blockade and adoptive T cell therapy. The term "cytotoxic CD8-positive T-cell mediated lysis of tumor cells" refers to a cellular process, not a specific molecular target or receptor, hence this entry describes a function and effector cell type rather than a canonical "target". For structured information systems, the appropriate canonical target would be "Cytotoxic CD8-positive T cell" or its functional products/signaling receptors, not the function itself[1][2][3][4][5].

Other names

Cytotoxic T lymphocyteCTLCD8+ T cellCD8+ cytotoxic T lymphocyteCD8+ T lymphocyte

Enhancement or suppression of CD8+ T cell cytotoxicity Modulation of immune checkpoints (PD-1/PD-L1, CTLA-4) Activation by tumor-specific antigens Perforin and granzyme-mediated target cell lysis Fas-FasL induced apoptosis Activation or blockade of NKG2D/NKG2DL axis[1][2][3]