Mouse Anti-Human HLA-ABC Antibody (S-5631)

HLA-ABC (also termed HLA class I classical heavy chains A, B, and C) are 44 kDa type I transmembrane glycoproteins encoded within the major histocompatibility complex on chromosome 6p21.3; each non-covalently associates with the invariant light chain β2-microglobulin (12 kDa) to form a peptide-binding heterodimer that is constitutively expressed on nearly all nucleated cells. These molecules serve as the principal conduit for presenting endogenously derived 8–11-mer peptides to CD8⁺ cytotoxic T lymphocytes, thereby orchestrating immune surveillance against intracellular pathogens, tumors, and transplanted tissues. Polymorphic residues concentrated in the α1 and α2 domains create an extraordinary diversity (thousands of alleles catalogued in the IPD-IMGT/HLA database), which underpins population-level resistance to infection yet constitutes the primary barrier to solid-organ and hematopoietic stem-cell transplantation through allorecognition. Beyond antigen presentation, HLA-ABC interacts with NK-cell inhibitory receptors (KIR and LILRB1) to calibrate natural killer cell responses, and its surface levels are dynamically modulated by cytokines such as interferon-γ, viral immune evasion proteins (e.g., HIV Nef, CMV US2/US11), and oncogenic signaling pathways, making quantitative HLA-ABC expression a prognostic biomarker in cancer immunotherapy.