Major histocompatibility complex class I A*02 molecule (HLA-A*02)

Major histocompatibility complex class I A*02 molecule (HLA-A*02) is a highly polymorphic cell surface glycoprotein encoded by the HLA-A gene, found on all nucleated human cells. It is a member of the major histocompatibility complex class I family, consisting of a polymorphic α chain (with α1, α2, and α3 domains) non-covalently associated with β2-microglobulin. HLA-A*02 binds peptide fragments (8–10 amino acids, derived from intracellular proteins) in its α1/α2 domain groove and presents them at the cell surface. The presented peptide-HLA complex is recognized by the T cell receptor of cytotoxic CD8+ T lymphocytes, enabling immune surveillance against infected or transformed (e.g., cancerous) cells. HLA-A*02 and other class I molecules are essential for immune system discrimination of self versus non-self, play key roles in the outcome of viral infections, autoimmunity, immunotherapy, and determine compatibility in organ transplantation. Its high allelic diversity (notably A*02:01, A*02:06, etc.) contributes to individual variability in immune responses and influences susceptibility and resistance to various diseases

Other names

HLA-A*02HLA-A2HLA class I A*02HLA-A*02:01 (most common allele)MHC class I A2

Peptide/hapten presentation to CD8+ T cells, triggering cytotoxic immune responses Targeted killing of cells displaying abnormal/self/non-self peptides presented on HLA-A*02 by engineered T cells, bispecific antibodies, or vaccines