MAGE-A1 peptide–HLA-A1 complex

The MAGE-A1 peptide–HLA-A1 complex is formed when a peptide derived from the melanoma antigen gene A1 (MAGE-A1, typically EADPTGHSY, residues 161–169) is bound by the human major histocompatibility complex class I molecule HLA-A1 and presented on the cell surface[1][3][4]. This complex acts as a target for cytotoxic CD8+ T cells, which recognize the peptide–MHC (pMHC) via their T cell receptors (TCRs), enabling immune surveillance against tumor cells expressing MAGE-A1. The MAGE-A1 protein is a canonical cancer/testis antigen, normally silent in most adult tissues but aberrantly expressed in a range of cancers, where it is processed into peptides for MHC class I binding[4]. Therapeutic strategies include the engineering of TCRs or adoptive T cell therapies able to specifically target the MAGE-A1 peptide–HLA-A1 complex to eliminate tumors, making this pMHC complex a validated therapeutic target in cancer immunotherapy[4][5]. Structural studies indicate unique conformational features and tight specificity in the interaction between the peptide, MHC, and TCR or therapeutic antibodies[1][3]. Monitoring MAGE-A1 expression and HLA-A1 status serves as a critical biomarker strategy for patient selection in these therapies[4].

Other names

HLA-A1:MAGE-A1 complexMAGE-A1/HLA-A1 complexMAGE-A1 pMHC complex

Recognition and killing of tumor cells by T cells whose TCRs specifically bind the MAGE-A1 peptide presented by HLA-A1 (CD8 T cell–mediated cytotoxicity)[4][5] Immune checkpoint blockade can enhance this process by preventing T cell inhibition (indirect)