HLA Class I Heavy Chain (HLA Class I)

HLA class I heavy chains are the α chains of human leukocyte antigen (HLA) class I molecules, which are essential components of the immune system. These molecules present intracellularly derived peptide antigens to CD8+ cytotoxic T lymphocytes, enabling immune surveillance and response against infected or malignant cells. The HLA class I molecule is a heterodimer composed of a polymorphic heavy chain (α chain), and a non-polymorphic light chain called β2-microglobulin (β2M). The α chain (~44–47 kDa) consists of three extracellular domains: α1, α2, and α3, a transmembrane region, and a short cytoplasmic tail. The α1 and α2 domains form the peptide-binding groove. The heavy chain is highly polymorphic—this diversity underlies individual differences in immune responses as different alleles present different sets of peptides.

Other names

MHC Class I Heavy ChainHuman Leukocyte Antigen Class I Heavy ChainHLA-AHLA-BHLA-CHLA-EHLA-FHLA-Galpha chain of HLA Class I

Modulation of T cell activation through altered antigen presentation.