CD8 is a transmembrane glycoprotein that acts as a co-receptor for the T-cell receptor (TCR). It plays a crucial role in T cell signaling and assists in cytotoxic T cell-antigen interactions. CD8 binds to a major histocompatibility complex (MHC) molecule but is specific for the MHC class I protein. The CD8 co-receptor is primarily expressed on the surface of cytotoxic T cells but can also be found on natural killer cells, cortical thymocytes, and dendritic cells. The CD8 molecule is a marker for the cytotoxic T-cell population.
When CD8+ T cells are activated, they express FasL on their cell surface, which binds to its receptor, Fas, on the target cell’s surface. This binding causes the Fas molecules on the target cell’s surface to trimerize, thereby bringing together signaling molecules.
References:
CD8 T cells.pdf (immunology.org)
