Tumor neoantigen peptide–Major Histocompatibility Complex (MHC) (NeoAg-MHC)

Tumor neoantigen peptide–Major Histocompatibility Complex (MHC) complexes are unique molecular signatures on the surface of cancer cells, formed when mutated proteins are processed into short peptides and presented by MHC molecules (also known as HLA in humans). Unlike tumor-associated antigens, neoantigens are derived from somatic mutations—such as single nucleotide variants or frameshifts—and are entirely absent from healthy tissues, providing a high degree of tumor specificity and reducing the risk of autoimmune side effects. These complexes are primarily recognized by T-cell receptors (TCRs) on CD8+ and CD4+ T cells, which triggers a targeted cytotoxic immune response against the tumor. Therapeutic strategies targeting these complexes include personalized mRNA or peptide vaccines, adoptive cell therapies like TCR-engineered T cells (TCR-T), and TCR-mimic antibodies or bispecific T-cell engagers. Despite their potential for precision medicine, challenges such as tumor heterogeneity, MHC downregulation as an escape mechanism, and the logistical complexity of personalized manufacturing remain significant hurdles in the clinical application of neoantigen-targeted therapies.

Other names

Neoantigen-HLA complexTumor-specific antigen-MHC complexpMHC (peptide-MHC) complexNeoepitope-MHC complexTSA-MHC complex

Recognition of the peptide-MHC complex by T-cell receptors (TCRs) on CD8+ or CD4+ T cells, leading to T-cell activation, proliferation, and the subsequent targeted lysis of tumor cells by cytotoxic T lymphocytes (CTLs).