Melanoma-associated antigen 3 (MAGE-A3) peptide-MHC complex (MAGE-A3/MHC)

Melanoma-associated antigen 3 (MAGE-A3) is a prominent member of the cancer-testis antigen (CTA) family, characterized by its restricted expression in male germ cells and its aberrant overexpression in various malignancies, including melanoma and non-small cell lung cancer (UniProt P43357). The therapeutic target is the specific complex formed when MAGE-A3-derived peptides, such as the HLA-A1-restricted EVDPIGHLY sequence, are processed and presented on the cell surface by Major Histocompatibility Complex (MHC) molecules. These peptide-MHC complexes serve as ligands for T-cell receptors (TCRs), making them primary targets for TCR-engineered T-cell (TCR-T) therapies and cancer vaccines (PubMed: 23580031). While MAGE-A3 is highly immunogenic, clinical trials of recombinant protein vaccines, such as GSK1572932A, failed to meet primary endpoints in large-scale Phase III studies like MAGRIT (PubMed: 26712287). Furthermore, TCR-T therapies targeting this complex have encountered significant safety hurdles, most notably fatal neurotoxicity caused by unexpected cross-reactivity with MAGE-A12 expressed in human brain tissue (PubMed: 23580031). Despite these challenges, MAGE-A3 remains a significant target in the development of next-generation immunotherapies, requiring precise patient selection based on both antigen expression and HLA genotype.

Other names

MAGE-A3MAGE3Cancer/testis antigen 1.3CT1.3Antigen MZ2-DMelanoma antigen family A 3

T-cell receptor binding to peptide-MHC complex, active immunization with recombinant protein or peptides, and T-cell mediated cytotoxicity