Melanoma-associated antigen A4 peptide–HLA class I complex (MAGE-A4 peptide–HLA-I complex)

The Melanoma-associated antigen A4 peptide–HLA class I complex is a molecular entity formed by the binding of a peptide from the cancer-testis antigen MAGE-A4 to a human leukocyte antigen (HLA) class I molecule, such as HLA-A*0201. The complex is displayed on the surface of tumor cells and is recognized by cytotoxic CD8+ T cells, which is central to immune targeting of cancer cells. MAGE-A4 is minimally expressed in adult tissues but highly expressed in various tumors, making it a preferred target for immunotherapies, including therapeutic cancer vaccines and engineered T-cell receptor (TCR)-based therapies. Structural studies have defined epitope features for T-cell recognition and have highlighted the importance of peptide-HLA conformational changes for immunogenicity. These properties establish the MAGE-A4 peptide–HLA class I complex as a therapeutic target primarily in oncology.

Other names

MAGE-A4/HLA-A2 complexHLA-A*0201/MAGE-A4 peptide complexMAGEA4 peptide–HLA-I complex

Induction of cytotoxic T lymphocyte (CTL) response against cancer cells expressing the MAGE-A4 antigen in context with HLA class I. Some therapeutics train T cells to recognize cancer cells via this complex.