Human leukocyte antigen A*02:01–Melanoma-associated antigen 3 peptide complex (HLA-A*02:01–MAGE-A3)

The HLA-A*02:01–MAGE-A3 peptide complex is a specific molecular target consisting of the Human Leukocyte Antigen (HLA) allele A*02:01 presenting a peptide fragment, typically the nonamer KVAELVHFL, derived from the Melanoma-associated antigen 3 (MAGE-A3) [1, 2]. MAGE-A3 is a member of the cancer-testis antigen family, which is characterized by high expression in various malignancies—such as melanoma, non-small cell lung cancer, and bladder cancer—while remaining silent in normal adult tissues, except for the testis and placenta [1, 3]. This expression pattern makes the HLA-A*02:01–MAGE-A3 complex an ideal target for T-cell-based immunotherapies, as it allows for the selective destruction of tumor cells by cytotoxic T lymphocytes [4]. Current therapeutic approaches include the development of TCR-engineered T-cells (TCR-T) and soluble TCR-bispecific molecules that recognize this specific peptide-MHC assembly [5]. However, the clinical application of these therapies is challenged by the risk of off-target toxicity, as seen in historical trials where TCRs cross-reacted with similar sequences in healthy tissues or other MAGE proteins, such as MAGE-A12 in the brain [6]. Consequently, rigorous specificity screening is essential for the development of safe and effective agents targeting this complex.

Other names

MAGE-A3–HLA-A*02:01 complexHLA-A2/MAGE-A3(112-120)MAGE-A3 pMHC complexKVAELVHFL–HLA-A*02:01 complex

Targeting of tumor cells through T-cell receptor (TCR) recognition of the specific peptide-MHC complex, leading to T-cell activation and directed lysis of the cancer cell.