Tumor-associated antigen-specific peptide-Major Histocompatibility Complex (pMHC)

Tumor-associated antigen-specific peptide-Major Histocompatibility Complex (pMHC) molecules are the primary targets for T-cell receptor (TCR)-engineered therapies, representing a bridge between the intracellular proteome and the immune system [1]. These complexes are formed when intracellular proteins are degraded into peptides and loaded onto MHC Class I or II molecules for presentation on the cell surface [4]. In oncology, these peptides are derived from tumor-associated antigens (TAAs) such as MAGE-A4, NY-ESO-1, or gp100, which are often overexpressed or uniquely expressed by malignant cells [2][3]. Unlike CAR-T cells, which are limited to recognizing surface proteins, TCR-based therapies can target the vast array of intracellular proteins presented as pMHCs, significantly expanding the range of targetable tumor antigens [1]. The clinical success of targeting pMHC depends on the high-affinity recognition by engineered TCRs while maintaining extreme specificity to avoid lethal cross-reactivity with similar peptides presented on vital healthy organs [2][5]. Current therapeutic applications include TCR-engineered T-cells (TCR-T) and Immune Mobilizing Monoclonal TCRs Against Cancer (ImmTACs) [3][4]. Sources: [1] Nature Reviews Clinical Oncology, "T-cell receptor-engineered T-cell therapy for solid tumors," 2021. [2] FDA, "Summary Basis for Regulatory Action: Tecelra (afamitresgene autoleucel)," 2024. [3] New England Journal of Medicine, "Overall Survival with Tebentafusp in Metastatic Uveal Melanoma," 2021. [4] Frontiers in Immunology, "The landscape of pMHC targets for cancer immunotherapy," 2020. [5] Journal of Hematology & Oncology, "TCR-T cell therapy: current status and future perspectives," 2022.

Other names

Tumor-specific pMHCHLA-peptide complexAntigen-MHC complexpMHC targetPeptide-HLA complex

Engineered T-cell receptors (TCRs) on infused T-cells or soluble TCR-based bispecific molecules bind with high affinity and specificity to the peptide-MHC complex on the tumor cell surface, triggering T-cell activation, the release of cytotoxic granules (perforin/granzyme), and cytokine production to induce tumor cell lysis [1][3].