Cluster of differentiation 8 molecule (CD8)

The cluster of differentiation 8 molecule (CD8) is a cell surface transmembrane glycoprotein predominantly expressed on cytotoxic T lymphocytes (CD8+ T cells) and, to a lesser extent, on natural killer cells, some cortical thymocytes, and dendritic cells[1][2][3][5][6]. CD8 functions as a crucial co-receptor for antigen-specific T cell activation, binding to the α3 domain of major histocompatibility complex class I (MHC-I) molecules on antigen-presenting cells. This stabilizes TCR–antigen–MHC interactions and amplifies signal transduction, facilitating targeted cytotoxic responses against infected, malignant, or otherwise abnormal cells. CD8 exists as either an alpha-alpha homodimer (CD8αα) or alpha-beta heterodimer (CD8αβ). It plays a pivotal role in immunity against intracellular pathogens and is routinely used as a biomarker for cytotoxic effector cells in immunology and cancer research[1][2][3][5][6].

Other names

CD8CD8 antigenCD8 co-receptorT8 antigenCluster of differentiation 8CD8A (alpha subunit)CD8B (beta subunit)CD8+ cell marker

Enhancement of anti-tumor immunity by activation of CD8+ T cells; Modulation of immune checkpoints to restore or potentiate CD8+ T cell cytotoxicity; Indirect engagement in cell-mediated cytotoxicity via TCR-MHC class I recognition[1][2][3][5]