Tumor-specific peptide-major histocompatibility complex (pMHC)

Tumor-specific peptide antigens presented by the Major Histocompatibility Complex (MHC) are critical molecular targets that allow the immune system to distinguish malignant cells from healthy tissue. These complexes, often referred to as peptide-MHC (pMHC) complexes, consist of short amino acid sequences derived from mutated (neoantigens) or overexpressed (tumor-associated) proteins that are processed and displayed on the cell surface by MHC Class I or Class II molecules (Nature Reviews Cancer, 2017). The T-cell receptor (TCR) on the surface of T-lymphocytes specifically recognizes these pMHC complexes, initiating a signaling cascade that leads to the targeted destruction of the cancer cell (Frontiers in Immunology, 2021). In modern oncology, these complexes serve as the primary targets for advanced immunotherapies, including TCR-engineered T-cell (TCR-T) therapies, bispecific T-cell engagers (BiTEs), and personalized cancer vaccines (NIH/NCI). For example, drugs like Tebentafusp target specific pMHC complexes (gp100/HLA-A*02:01) to redirect T-cells against uveal melanoma (FDA, 2022). While highly specific, the therapeutic utility of these targets can be limited by the downregulation of MHC molecules by tumors as a mechanism of immune escape and the risk of cross-reactivity with similar peptides found in vital organs (PubMed, 2023).

Other names

Neoantigen-MHC complexTumor-specific antigen-MHC complexpMHC complexPeptide-HLA complexTumor-associated antigen-MHC complexTSA-MHC

T-cell receptor (TCR) binding and activation, redirected T-cell cytotoxicity, immune synapse formation