Major histocompatibility complex class I molecule H-2K^b (H-2K^b)

Major histocompatibility complex class I molecule H-2K^b is a mouse cell-surface glycoprotein and member of the MHC class I family. It is composed of a polymorphic heavy α chain (with α1, α2, and α3 domains), non-covalently associated with an invariant β2-microglobulin light chain. H-2K^b binds short peptides (typically 8–10 amino acids) derived from endogenous proteins, including viral, tumor, and self-antigens. Peptides are bound in a groove formed by the α1 and α2 domains, with both termini tightly anchored by conserved contacts. The stable peptide–MHC complex is presented at the cell surface where it can be recognized by cytotoxic (CD8+) T lymphocytes via their T cell receptors, triggering immune responses and elimination of infected or transformed cells. H-2K^b is the canonical MHC class I allele in the C57BL/6 mouse strain and is widely used in experimental immunology. No drugs directly target H-2K^b in clinical use, but it is essential for preclinical studies of antigen presentation, vaccine design, and immune checkpoint modulation. Its dysfunction or mismatching plays a role in transplant rejection, infectious immunity, and tumor immune surveillance.

Other names

H-2K^bMHC class I H-2K^bMouse MHC class I K^b moleculeK^b

Presentation of peptide epitopes enables recognition by T-cell receptors on CD8+ cytotoxic T-lymphocytes, leading to immune cell activation and potential target cell lysis. Recognition of the peptide-MHC complex can trigger immune-mediated killing of infected or malignant cells.