Melanoma-associated antigen 9 peptide presented by Human Leukocyte Antigen A*02:01 (MAGE-A9/HLA-A*02:01)

The MAGE-A9 peptide presented by HLA-A*02:01 is a specific peptide-major histocompatibility complex (pMHC) found on the surface of various malignant cells (UniProt: P43362). MAGE-A9 belongs to the Type I Cancer-Testis Antigen (CTA) family, which is characterized by high expression in tumors but restricted expression in normal adult tissues, primarily the testis and placenta, where HLA molecules are absent (PMID: 21854401). This restricted expression pattern makes the MAGE-A9/HLA-A*02:01 complex an ideal target for T-cell-based immunotherapies, such as TCR-engineered T-cells (TCR-T) and bispecific T-cell engagers (PMID: 30105410). In clinical contexts, MAGE-A9 is frequently overexpressed in bladder cancer, non-small cell lung cancer, and esophageal squamous cell carcinoma, often correlating with poor prognosis and advanced disease stages (PMID: 25415230). Therapeutic strategies targeting this complex involve the use of high-affinity T-cell receptors or TCR-mimetic antibodies that specifically recognize the MAGE-A9 peptide (typically the ALSVMGVYV sequence) in the groove of the HLA-A*02:01 molecule. By binding to this complex, these therapies trigger a potent cytotoxic immune response against the tumor cells while sparing healthy tissues, although challenges remain regarding potential cross-reactivity with other MAGE-A family members due to high sequence homology.

Other names

MAGEA9/HLA-A*02:01MAGE-A9 peptide-MHC complexMelanoma antigen family A 9 peptide presented by HLA-A2CT1.9 peptide-MHC complex

Targeting of the peptide-MHC complex by engineered T-cell receptors (TCRs) or TCR-mimetic antibodies to induce T-cell mediated lysis of tumor cells.