Melanoma antigen-specific peptide–MHC complex (Melanoma pMHC)

Melanoma antigen-specific peptide–MHC (pMHC) complexes are molecular assemblies presented on the surface of melanoma cells, consisting of an 8-11 amino acid peptide derived from tumor-associated antigens (TAAs) bound to a Major Histocompatibility Complex (MHC) molecule, typically HLA-A*02:01 (PMID: 26814019). These complexes serve as the specific ligands for T-cell receptors (TCRs), allowing the adaptive immune system to distinguish malignant cells from healthy ones (PMID: 29942032). Common melanoma antigens presented in this manner include gp100, MAGE-A4, NY-ESO-1, and MART-1, which are often overexpressed in tumors but have restricted expression in normal tissues (PMID: 23913171). Therapeutic interventions such as TCR-engineered T-cells (TCR-T) and Immune Mobilizing Monoclonal TCRs Against Cancer (ImmTACs) are designed to bind these pMHC complexes with high specificity and affinity to trigger tumor lysis (PMID: 34551229). For instance, Tebentafusp is a bispecific protein that targets the gp100:HLA-A*02:01 complex to redirect T-cells toward uveal melanoma cells (PMID: 34551229). Clinical challenges include the requirement for specific patient HLA types, potential off-target toxicity due to cross-reactivity with similar self-peptides, and tumor escape through MHC downregulation (PMID: 30241496).

Other names

Melanoma-associated antigen-HLA complexTumor-associated antigen-MHC complexTAA-pMHCMelanoma pMHC complexSpecific peptide-MHC class I complex

High-affinity TCR-mediated recognition of peptide-MHC complexes leading to T-cell activation, cytokine release, and directed lysis of antigen-presenting tumor cells.