CD8 alpha&beta Heterodimer His Tag&Flag Tag Protein, Human

CD8 (cluster of differentiation 8) is a transmembrane glycoprotein expressed on cytotoxic T lymphocytes, serving as a coreceptor for the T cell receptor (TCR). It exists primarily as a CD8αβ heterodimer or a CD8αα homodimer, each chain belonging to the immunoglobulin superfamily. Functionally, its extracellular IgV-like domain binds the α3 domain of MHC class I molecules, stabilizing the TCR-antigen interaction. Concurrently, its cytoplasmic tail recruits the kinase Lck to initiate intracellular signaling cascades crucial for T cell activation and target cell killing. CD8 is thus essential for adaptive immunity against viruses and tumors.