Neoantigen-peptide-MHC complex (NeoAg-pMHC complex)

The neoantigen-peptide-MHC (pMHC) complex is a fundamental target in personalized cancer immunotherapy, representing the unique molecular signature of a tumor cell as recognized by the adaptive immune system. Neoantigens are novel peptides derived from tumor-specific somatic mutations, such as single nucleotide variants or gene fusions, which are absent in the normal genome and thus bypass central thymic tolerance. These peptides are processed intracellularly and presented on the cell surface by Major Histocompatibility Complex (MHC) molecules, forming a complex that is specifically recognized by the T-cell receptor (TCR) on CD8+ or CD4+ T cells. Therapeutic strategies targeting these complexes include the infusion of autologous T cells engineered with patient-specific TCRs (TCR-T therapy) or the administration of personalized vaccines designed to elicit an endogenous T-cell response against these neoepitopes. By focusing on mutations unique to the individual patient's tumor, these therapies aim to achieve potent anti-tumor activity while sparing healthy tissues from off-target effects. However, the effectiveness of targeting these complexes can be challenged by tumor heterogeneity, MHC downregulation, and the potential for T-cell exhaustion within the immunosuppressive tumor microenvironment.

Other names

Neoantigen-MHC complexpMHC complexTumor-specific antigen-MHC complexNeoepitope-HLA complexMutation-derived antigen-MHC complexPatient-specific neoantigen-specific T-cell receptor complex

The therapeutic agent (e.g., an engineered TCR-T cell or a vaccine-induced T cell) possesses a T-cell receptor (TCR) that specifically recognizes a unique neoantigen peptide presented by the patient's Major Histocompatibility Complex (MHC) molecules on the surface of tumor cells. This binding event triggers the TCR-CD3 signaling cascade, leading to the activation of the T cell, secretion of cytotoxic granules such as perforin and granzymes, and production of pro-inflammatory cytokines like IFN-gamma and TNF-alpha, ultimately resulting in the selective destruction of the neoantigen-expressing tumor cells.