HLA-A*01-restricted melanoma-associated peptide-MHC class I complex (HLA-A1 pMHC) (HLA-A1 pMHC)

HLA-A1-restricted melanoma-associated peptide–MHC class I complexes are specialized molecular assemblies presented on the surface of melanoma cells to signal the presence of tumor-specific proteins to the immune system. These complexes consist of the HLA-A*01:01 heavy chain, beta-2 microglobulin, and a short peptide fragment derived from melanoma-associated antigens such as MAGE-A3, MAGE-A1, or Tyrosinase (Trautmansdorff et al., 2019, Frontiers in Immunology). Their primary biological function is to serve as a ligand for CD8+ T-cell receptors (TCRs), facilitating the recognition and destruction of malignant cells by the cellular immune system (Janeway's Immunobiology). In drug development, these complexes are targeted by TCR-engineered T-cell therapies (TCR-T) and TCR-mimetic antibodies, which are designed to recognize the specific peptide-HLA interface with high affinity. While these targets offer high tumor specificity due to the restricted expression of certain melanoma antigens, they pose significant safety challenges. A notable example is the cross-reactivity of MAGE-A3/HLA-A1-specific TCRs with the muscle protein Titin, which resulted in severe cardiotoxicity in clinical trials (Linette et al., 2013, Blood). Consequently, these complexes represent a potent but high-risk class of therapeutic targets requiring precise molecular engineering and patient stratification based on HLA typing and antigen expression.

Other names

HLA-A*01:01-peptide complexMAGE-A3/HLA-A1 complexMelanoma antigen-MHC class I complexpMHC class I complexHLA-A1-restricted melanoma-associated peptide–MHC class I complexes

Targeted recognition of the peptide-MHC complex by engineered T-cell receptors (TCRs) or antibodies, leading to T-cell activation, secretion of cytotoxic granules (perforin/granzyme), and induction of apoptosis in the target tumor cell (Janeway's Immunobiology).