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

Tumor-derived neoantigen peptides presented on patient MHC-I/II molecules are highly specific therapeutic targets that arise from non-synonymous somatic mutations unique to an individual's tumor (Schumacher & Schreiber, Science, 2015). These mutated proteins are processed into short peptides and displayed on the cell surface by Major Histocompatibility Complex (MHC) molecules, where they serve as 'non-self' signals to the adaptive immune system (Hacohen et al., Cancer Immunology Research, 2013). Because these neoantigens are absent from healthy tissues, they bypass central thymic tolerance, allowing for the generation of high-avidity T-cell responses with minimal risk of damage to normal cells (Ott et al., Nature, 2017). In clinical practice, these complexes are targeted using personalized immunotherapy platforms, such as mRNA vaccines (e.g., mRNA-4157) and TCR-engineered T cells, which are custom-designed based on a patient's specific mutational profile (Sahin & Türeci, Science, 2018). The efficacy of these treatments is closely linked to the tumor mutational burden and the quality of the peptide-MHC binding (Yarchoan et al., NEJM, 2017). However, the high degree of patient specificity requires complex bioinformatic identification and individualized manufacturing, presenting significant logistical challenges. Furthermore, tumors may evolve to evade detection by downregulating MHC expression or losing the targeted neoantigen (Gettinger et al., Cancer Discovery, 2017).

Other names

Neoepitope-HLA complexTumor-specific antigen (TSA)Mutated peptide-MHC complexNeoantigen-HLA complexPersonalized tumor antigen

Therapeutic agents targeting these complexes function by stimulating a patient's immune system to recognize unique tumor mutations. Vaccines (mRNA, DNA, or peptide-based) provide the genetic code or physical peptide of the neoantigen to antigen-presenting cells, which then display the neoepitope on MHC molecules to prime and expand neoantigen-specific CD8+ and CD4+ T cells (Sahin & Türeci, Science, 2018). Additionally, adoptive cell therapies use T cells engineered with T-cell receptors (TCRs) that specifically bind the neoantigen-MHC interface, triggering direct cytotoxic lysis of the tumor cell (Schumacher & Schreiber, Science, 2015).