Tumor-specific mutant peptide–HLA complex (NeoAg-HLA)

Tumor-specific mutant peptide–HLA complexes are unique molecular targets formed when somatic mutations in a cancer cell's genome result in altered proteins. These mutated proteins are processed into short peptides, known as neoantigens, and presented on the cell surface by Human Leukocyte Antigen (HLA) molecules (Blass and Ott, Nature Reviews Clinical Oncology, 2021). Because these neoantigens are derived from non-synonymous mutations absent from the normal human genome, they are highly specific to the tumor, making them ideal targets for personalized immunotherapy. Recognition of these complexes by neoantigen-reactive T-cell receptors (TCRs) triggers a potent and specific immune response against the malignant cells. Therapeutic strategies targeting these complexes include personalized neoantigen vaccines (mRNA, DNA, or peptide-based) and adoptive cell therapies using TCR-engineered T cells. These approaches aim to expand the population of T cells that can specifically identify and destroy cells displaying the mutant pHLA complex. However, the high degree of patient specificity requires individualized manufacturing, and the potential for tumor immune evasion through HLA downregulation or loss of heterozygosity presents significant clinical challenges (Yarchoan et al., NEJM, 2017). Despite these hurdles, targeting neoantigen-HLA complexes remains a cornerstone of next-generation precision oncology.

Other names

Neoantigen-MHC complexMutant peptide-MHC (pMHC)Tumor-specific antigen (TSA)-HLA complexNeoepitope-HLA complexPersonalized neoantigen-HLA complex

Recognition of the mutant peptide-HLA complex by endogenous or engineered T-cell receptors (TCRs) leads to the formation of an immunological synapse, resulting in the release of perforins and granzymes that induce apoptosis in the target tumor cell (Schumacher and Schreiber, Science, 2015).