Minor Histocompatibility Antigen HA-1

**Semantic type:** Amino Acid, Peptide, or Protein|Immunologic Factor

**Definition:** A peptide antigen comprised of 9 amino acids (VLHDDLLEA) that is derived by antigen processing from a variant of Rho GTPase-activating protein 45 where the arginine at amino acid residue 139 is substituted with histidine. This peptide can be presented by MHC class I HLA-A*0201 expressing cells. The complex of this peptide with HLA-A elicits donor-cytotoxic T-lymphocyte (CTL) reactivity following treatment by HLA-identical allogenic bone marrow transplant.

**Synonyms:** - HA-1 - HA-1(H) - mHag HA-1