Major histocompatibility complex class II-melanoma-associated antigen 3 peptide complex (MHC II-MAGE-A3)

The Major histocompatibility complex (MHC) class II-melanoma-associated antigen 3 (MAGE-A3) peptide complex is a specific molecular target formed when the MAGE-A3 protein is processed and its peptide fragments are presented on the cell surface by MHC class II molecules (PubMed: 11160658). MAGE-A3 is a prominent member of the cancer-testis antigen family, characterized by high expression in various tumors—such as melanoma, non-small cell lung cancer, and bladder cancer—while being restricted in normal tissues to the immune-privileged testis and placenta (UniProt P43357). This expression pattern makes the MAGE-A3/MHC II complex an ideal target for immunotherapy, as it allows the immune system to distinguish malignant cells from healthy ones. Therapeutic approaches targeting this complex include peptide-based vaccines and adoptive T-cell therapies using T-cell receptors (TCRs) engineered to recognize the specific peptide-MHC assembly (PubMed: 32433941). These treatments aim to activate CD4+ helper T cells, which play a crucial role in orchestrating a sustained anti-tumor response and enhancing the activity of cytotoxic CD8+ T cells. However, clinical development has faced challenges, including the need for precise HLA matching (e.g., HLA-DPB1*04:01) and the risk of off-target effects if the TCR cross-reacts with similar peptides from other MAGE family proteins (PubMed: 23838278).

Other names

HLA class II-MAGE-A3 complexMAGE-A3/MHC II complexMAGE-A3 peptide-HLA-DPB1*04:01 complexMelanoma-associated antigen 3 presented by MHC class II

T-cell receptor (TCR) recognition and binding to the peptide-MHC complex, leading to CD4+ T-cell activation and subsequent anti-tumor immune response (PubMed: 11160658).