Patient-specific tumor neoantigen or tumor-associated antigen–Major Histocompatibility Complex (MHC) complex (NeoAg-MHC/TAA-MHC)

Patient-specific tumor neoantigen or tumor-associated antigen–Major Histocompatibility Complex (MHC) complexes represent the fundamental unit of recognition for the adaptive cellular immune system in oncology. These complexes are formed when intracellular proteins—either mutated 'neoantigens' unique to the tumor or 'tumor-associated antigens' (TAAs) that are overexpressed—are processed into short peptides and loaded onto MHC Class I or II molecules for surface presentation (Source: Nature Reviews Cancer, 2021). In the context of immunotherapy, these complexes serve as highly specific targets that allow the immune system to distinguish malignant cells from healthy tissue (Source: Frontiers in Immunology, 2020). Therapeutic strategies such as TCR-engineered T-cell therapies (TCR-T) and personalized cancer vaccines are designed to recognize these specific peptide-MHC (pMHC) combinations to trigger a targeted cytotoxic T-cell response (Source: Science, 2017). Because neoantigens arise from somatic mutations unique to an individual's tumor, they are considered ideal targets for high-specificity immunotherapy with a lower risk of inducing central tolerance compared to shared antigens (Source: Journal of Experimental Medicine, 2019). However, the clinical success of targeting these complexes is often challenged by the heterogeneity of antigen expression and the ability of tumors to evade detection by downregulating their MHC presentation machinery (Source: PubMed, PMID: 30559448).

Other names

Tumor-specific antigen-MHC complexNeoepitope-HLA complexPeptide-MHC complexpMHCTumor-associated antigen-HLA complexCancer-specific antigen-MHC complex

Therapeutic agents target these complexes via engineered T-cell receptors (TCR-T) or bispecific molecules that recognize the specific peptide-MHC binding interface, or via vaccines that prime the endogenous immune system to recognize these complexes, leading to the activation of cytotoxic T-lymphocytes (CTLs) and subsequent lysis of tumor cells.