Melanoma-associated antigen 1 peptide–Major Histocompatibility Complex class I complex (MAGE-A1–MHC I complex)

The MAGE-A1 peptide–MHC class I complex is a tumor-specific antigenic target formed by the presentation of intracellularly processed Melanoma-associated antigen 1 (MAGE-A1) fragments on the surface of malignant cells. MAGE-A1 is a member of the cancer-testis antigen (CTA) family, which is characterized by restricted expression in immune-privileged germ cells and aberrant reactivation in various cancers, such as melanoma, non-small cell lung cancer, and multiple myeloma. Since germ cells do not express MHC class I molecules, the presentation of MAGE-A1 peptides (such as EADPTGHSY for HLA-A*01:01 or KVLPDTFPI for HLA-A*02:01) is highly specific to tumor cells. This complex serves as a critical recognition site for T-cell receptors (TCRs), making it a primary target for TCR-engineered T-cell (TCR-T) therapies and TCR-like bispecific antibodies. These therapeutic modalities are designed to bind the specific peptide-HLA configuration, triggering T-cell activation and subsequent lysis of the target tumor cell. Clinical success depends on the precise matching of the patient's HLA haplotype and the presence of MAGE-A1 expression within the tumor tissue.

Other names

MAGE-A1/HLA complexMAGE-A1/HLA-A1 complexMAGE-A1/HLA-A2 complexMelanoma antigen family A 1 peptide-MHC complexpMHC MAGE-A1

T-cell receptor (TCR) binding to the peptide-MHC complex, leading to T-cell activation, cytokine release (IFN-gamma, TNF-alpha), and granzyme/perforin-mediated tumor cell lysis.