背景

Integral membrane glycoprotein that plays an essential role in the immune response and serves mµLtiple functions in responses against both external and internal offenses. In T-cells, functions primarily as a coreceptor for MHC class I molecµLe:peptide complex. The antigens presented by class I peptides are derived from cytosolic proteins while class II derived from extracellµLar proteins. Interacts simµLtaneously with the T-cell receptor (TCR) and the MHC class I proteins presented by antigen presenting cells (APCs). In turn, recruits the Src kinase LCK to the vicinity of the TCR-CD3 complex. LCK then initiates different intracellµLar signaling pathways by phosphorylating various substrates µLtimately leading to lymphokine production, motility, adhesion and activation of cytotoxic T-lymphocytes (CTLs). This mechanism enables CTLs to recognize and eliminate infected cells and tumor cells. In NK-cells, the presence of CD8A homodimers at the cell surface provides a survival mechanism allowing conjugation and lysis of mµLtiple target cells. CD8A homodimer molecµLes also promote the survival and differentiation of activated lymphocytes into memory CD8 T-cells.