Melanoma-associated antigen 3-derived HLA-A*0201-restricted epitope (MAGE-A3/HLA-A*0201)

The Melanoma-associated antigen 3 (MAGE-A3)-derived HLA-A*0201-restricted epitope is a specific peptide-MHC complex consisting of a MAGE-A3 fragment presented by the Human Leukocyte Antigen A*02:01 molecule (PMID: 24501219). MAGE-A3 is a cancer-testis antigen that is highly expressed in various solid tumors, such as melanoma and non-small cell lung cancer, but is absent in normal tissues except for the immune-privileged testes (PMID: 26787749). This restricted expression pattern makes the epitope a prime target for cancer immunotherapies, including therapeutic vaccines and engineered T-cell receptor (TCR) T-cell therapies. The most commonly targeted peptide sequence within this complex is the decamer FLWGPRALV (MAGE-A3 271-279). Clinical trials targeting this epitope have encountered severe safety challenges, most notably fatal off-target cross-reactivity. Specifically, some TCR-T therapies demonstrated fatal cardiotoxicity due to cross-reactivity with the muscle protein Titin (PMID: 23765104). Other trials reported neurotoxicity caused by cross-reactivity with the MAGE-A12 protein in the brain (PMID: 23917459). Despite these setbacks, the epitope remains a high-value target for next-generation precision oncology. Current research focuses on improving TCR specificity to ensure that therapeutic agents do not recognize similar self-peptides in healthy tissues. Successful targeting of this epitope could provide a potent treatment option for patients with MAGE-A3-positive, HLA-A*02:01-positive malignancies.

Other names

MAGE-A3 peptide FLWGPRALVMAGE-A3 271-279MAGE-A3/HLA-A2 complexMAGE-A3/HLA-A*02:01

Activation of antigen-specific CD8+ T cells through T-cell receptor (TCR) binding to the peptide-MHC complex, leading to tumor cell lysis.