CD8 beta chain antigen (CD8B)

The **CD8 beta chain antigen** is one of two polypeptide chains (alpha and beta) forming the CD8 co-receptor, a type I transmembrane glycoprotein found chiefly on cytotoxic (CD8+) T lymphocytes. The CD8 co-receptor binds to an invariant domain of the major histocompatibility complex class I (MHC-I) molecule, distinct from the antigen binding region, thereby facilitating the interaction between the T-cell receptor and antigen-presenting cells. The CD8 beta chain partners with the CD8 alpha chain to form heterodimers (CD8αβ) on the majority of cytotoxic T cells, playing a central role in immune surveillance, cellular cytotoxicity, and signal transduction via recruitment of Lck kinase. Genetic and post-translational modifications (e.g. glycosylation of the hinge region) modulate its affinity and function. CD8 beta, as part of the CD8 complex, is implicated in diverse pathological contexts including cancer, infectious disease, and autoimmunity, and represents a targetable node for immunotherapies.

Other names

CD8BCD8 betaCluster of Differentiation 8 beta chainCytotoxic T-cell co-receptor beta chain

Antagonism or depletion (anti-CD8 antibodies block or remove CD8+ T cells); Immunomodulation (altering function of CD8+ T cells, e.g. glycosylation modifications of the hinge region); Enhancement of TCR/MHC-I sensitivity or signal transduction for boosting immune response