Human CD8A / CD8 Alpha Protein (Recombinant)

LifeSpan BioSciences

Human CD8A / CD8 Alpha Protein (Recombinant)

14

Research Use Only

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Cluster of differentiation 8 (CD8), a type I transmembrane glycoprotein of the immunoglobulin family of receptors, plays an integral role in signal transduction, and T cell differentiation and activation. CD8 is predominantly expressed on T cells as a disulfide-linked heterodimer of CD8a and CD8beta, where it functions as a co-receptor, along with T cell receptor (TCR), for major histocompatibilty complex class I (MHC-I) molecules; whereas its counterpart, CD4, acts as a co-receptor for MHC-II molecules. CD8 exists on the cell surface, where the CD8a 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 CD8a. Ligation of MHC-I/peptide complexes presented by antigen-presenting cells (APCs), triggers the recruitment of lymphocyte-specific protein tyrosine kinase (Lck), which leads to lymphokine production, motility and cytotoxic T lymphocyte (CTL) activation. Once activated, CTLs play a crucial role in the clearance of pathogens and tumor cells. Differentiation of naive CD8+ T cells into CTLs is strongly enhanced by IL-2, IL-12 and TGF-beta1. CHO cell-derived Recombinant Human sCD8a is a monomeric glycoprotein of 161 amino acid residues, which corresponds to the extracellular domain of CD8a. CHO cell-derived Recombinant Human sCD8a has a calculated molecular weight of 17.6 kDa; however, due to glycosylation, it migrates at an apparent molecular weight of approximately 27-29 kDa by SDS-PAGE analysis, under reducing conditions.

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