Peptide-major histocompatibility complex–T cell receptor complex (TCR–peptide–MHC complex)

The peptide–major histocompatibility complex–T cell receptor (TCR–peptide–MHC) complex is a fundamental tri-molecular structure at the core of adaptive cellular immunity. The complex forms when a short antigenic peptide, bound within the groove of an MHC class I or II molecule on an antigen-presenting cell surface, is recognized and bound by a clonotypic αβ TCR on a T cell. This interaction is central to T cell activation, specificity, and the discrimination of self versus non-self peptides, underlining its critical role in immune surveillance, response to infection, tumor recognition, and the development of immunotherapies. Therapeutic exploitation of this complex includes cancer immunotherapy via engineered TCR-T cells, peptide vaccines, and TCR-mimic antibodies, but safety challenges remain due to the potential for off-target effects and immune system misdirection.

Other names

TCR–pMHC complexT-cell receptor–peptide–MHC complexTCR–peptide–major histocompatibility complexTCR–MHC–peptide complex

Drugs targeting this complex typically aim to: Enhance TCR recognition and binding to specific pMHC targets (often tumor- or pathogen-derived peptides); Block or redirect the immune response (as in TCR-mimic antibodies or engineered T cells); Suppress autoreactive TCR-pMHC interactions in autoimmunity