huCD8A Mouse

CD8a (CD8 antigen, alpha chain) is a type I transmembrane glycoprotein primarily expressed on the surface of cytotoxic T lymphocytes (CTLs). As a member of the immunoglobulin superfamily, it serves as a critical co-receptor in T cell-mediated adaptive immune responses ^[1]. CD8a forms heterodimers (CD8αβ) with CD8b or homodimers (CD8αα) via disulfide bonds, and together with the T cell receptor (TCR), recognizes antigenic peptides presented by MHC class I molecules on antigen-presenting cells (APCs). Through its cytoplasmic domain, CD8a recruits the LCK tyrosine kinase, initiating the T cell activation signaling cascade and promoting CTL proliferation, differentiation, and cytotoxic function ^[2-3]. The CD8A gene is located on human chromosome 2 (2p12), and the CD8α chain it encodes plays a central role in anti-tumor immune surveillance, antiviral immunity, and autoimmune disease regulation. Targeting the CD8 co-receptor signaling pathway or CD8+ T cell-based adoptive cell therapies (e.g., CAR-T, TCR-T) have become important strategies in tumor immunotherapy ^[4-5].

The huCD8A mouse is a humanized model generated through gene editing technology, in which the endogenous extracellular domain of mouse Cd8a was replaced with the human CD8A extracellular domain, while the murine signal peptide, helical and cytoplasmic regions were retained. This model is suitable for in vivo efficacy and safety evaluation of antibody‑based therapeutics and CAR‑T/TCR‑T cell therapies targeting human CD8A, as well as for studying the functional mechanisms of CD8+ T cells in tumor immunity and infectious diseases.