Biotinylated CD8 alpha/CD8A His&Avi Tag Protein, Human

CD8α (the CD8 alpha chain, encoded by CD8A) is the α chain of the CD8 co-receptor, a type I transmembrane glycoprotein of the immunoglobulin superfamily composed of an extracellular Ig-like V domain, hinge and transmembrane regions, and a short cytoplasmic tail. It assembles with CD8β into the CD8αβ heterodimer or as the CD8αα homodimer. As a co-receptor for the T-cell receptor (TCR), CD8α binds MHC class I molecules and recruits Lck, thereby increasing antigen-recognition sensitivity and lowering the activation threshold of cytotoxic T cells; its expression also modulates TCR specificity and avidity. Clinically, CD8α/CD8 has become an attractive target: CD8 cis-targeted IL-2 selectively reactivates dysfunctional CD8⁺ T cells against chronic hepatitis B; CD8-targeted DARPin-AAV enables in vivo T-cell gene delivery and CAR engineering; CD8-targeted nanobody PET tracers such as SNA006 non-invasively monitor tumour CD8⁺ T-cell infiltration and immunotherapy response; and CD8α hinge/transmembrane domains improve CAR-T affinity and antitumour efficacy.