Rat Anti-Mouse MHC Class I (H-2) Antibody (S-5545)

MHC Class I (H-2) is the mouse major histocompatibility complex class I system, the murine equivalent of the human HLA class I molecules, encoded by genes within the H-2 complex located on mouse chromosome 17. The classical H-2 class I genes comprise H-2K, H-2D, and H-2L, which correspond functionally to the human HLA-A, HLA-B, and HLA-C genes and are highly polymorphic, with over 100 alleles identified for H-2K and H-2D. Like all MHC class I molecules, H-2 class I antigens are heterodimers consisting of a polymorphic transmembrane α heavy chain (approximately 45 kDa) non-covalently associated with the invariant light chain β2-microglobulin (12 kDa, encoded on chromosome 2). The heavy chain contains three extracellular domains (α1, α2, and α3), with α1 and α2 folding together to form the peptide-binding groove that accommodates short peptides typically 8–10 amino acids in length, while α3 adopts an immunoglobulin fold and interacts with the CD8 co-receptor. H-2 class I molecules are expressed on the surface of nearly all nucleated cells and present endogenous peptide antigens—derived from intracellular proteins including viral and tumor antigens—to CD8⁺ cytotoxic T lymphocytes, thereby enabling immune surveillance of infected and transformed cells. In addition to the classical genes, the H-2 complex also contains non-classical class I genes such as H-2Q, H-2T, and H-2M within the Tla region, which exhibit limited polymorphism and restricted tissue expression patterns, with functions that remain incompletely understood. The H-2 system is central to antigen presentation and transplantation immunology in mouse models, and its peptide-binding specificity defines the repertoire of epitopes recognized by CD8⁺ T cells in H-2ᵇ strains such as C57BL/6.