CD8 Proteins

Protein Information

CD8, also known as cluster of differentiation 8, is a type I transmembrane glycoprotein of the immunoglobulin family that plays a crucial role in T cell differentiation, activation, and signal transduction. It is expressed as either a heterodimer (CD8 alpha beta) or a homodimer (CD8 alpha alpha). The CD8 alpha beta form is predominantly found on the majority of thymocytes and a subpopulation of mature alpha beta TCR T cells, while the CD8 alpha alpha form is expressed on gamma delta TCR T cells, a subset of intestinal intraepithelial lymphocytes (IELs), and dendritic cells. CD8 functions as a co-receptor for major histocompatibility complex class I (MHC-I) molecules, working alongside the T cell receptor (TCR). The CD8 alpha chain is essential for binding to MHC-I. CD8 is also expressed on a subset of T cells, NK cells, monocytes, and dendritic cells as disulfide-linked homodimers of CD8 alpha. Upon ligation of MHC-I/peptide complexes presented by antigen-presenting cells (APCs), CD8 recruits lymphocyte-specific protein tyrosine kinase (Lck), leading to lymphokine production, increased motility, and activation of cytotoxic T lymphocytes (CTLs). Activated CTLs are vital for clearing pathogens and tumor cells. The differentiation of naive CD8+ T cells into CTLs is strongly enhanced by cytokines such as IL-2, IL-12, and TGF-beta1. Through its interactions with MHC-I and association with protein tyrosine kinase p56lck, CD8 plays a significant role in T cell development and the activation of mature T cells.

Synonyms

BB154331; CD8; CD8 alpha; CD8 alpha chain; CD8 alpha chain-like; CD8 antigen 32 kDa chain; CD8 antigen 37 kDa chain; CD8 antigen alpha polypeptide; CD8 antigen alpha protein; CD8 antigen alpha protein precursor; CD8 antigen alpha-chain; CD8 antigen beta polypeptide; CD8 antigen beta polypeptide precursor; CD8 antigen beta-chain; CD8 antigen, alpha chain; CD8 antigen, alpha polypeptide; CD8 antigen, alpha polypeptide (p32); CD8 antigen, alpha-chain; CD8 antigen, beta chain; CD8 antigen, beta chain 1; CD8 antigen, beta polypeptide; CD8 antigen, beta polypeptide 1 (p37); CD8 antigen, beta-chain; CD8 beta; CD8 beta chain; CD8 beta-2; CD8A; CD8a molecule; CD8A; T-cell surface glycoprotein; CD8alpha; CD8B; CD8b antigen; CD8b molecule; Cd8b1; CD8beta; fCD8; LEU2; Leu-2; Leu2 T-lymphocyte antigen; leu-2a; LOC100356269; Ly-2; LY3; Ly-3; Ly-35; Ly-B; Ly-C; Lymphocyte antigen 3; Lyt2; Lyt-2; Lyt-2.1 lymphocyte differentiation antigen (AA at 100); Lyt3; Lyt-3; MAL; OKT8 T-cell antigen; OX-8 membrane antigen; p32; P37; RHACD8-4; T cell co-receptor; T lymphocyte surface glycoprotein beta chain; T8 T-cell antigen; T-cell antigen Leu2; T-cell membrane glycoprotein Ly-3; T-cell surface glycoprotein; T-cell surface glycoprotein CD8 alpha chain; T-cell surface glycoprotein CD8 beta chain; T-cell surface glycoprotein Lyt-2; T-cell surface glycoprotein Lyt-3; T-cell surface molecule; T-lymphocyte differentiation antigen T8/Leu-2