Peptide–major histocompatibility complex–T cell receptor complex (pMHC–TCR complex)

The peptide–major histocompatibility complex–T cell receptor complex is the fundamental molecular assembly through which T lymphocytes recognize antigens. The complex consists of a short peptide antigen presented in the binding groove of an MHC molecule (class I or II) on the surface of antigen-presenting cells. The T cell receptor, composed usually of α and β chains (with variable regions responsible for antigen recognition), binds to both the peptide and the MHC molecule, forming a highly specific interface largely governed by complementarity-determining regions (CDRs)[3][5][6]. This interaction initiates signal transduction cascades resulting in T cell activation and a targeted immune response. Structural studies show a highly conserved diagonal docking of TCR over peptide–MHC, which is essential for specificity and diversity of antigen recognition. The complex plays central roles in health (infection control, cancer surveillance, immune tolerance) and disease (autoimmunity, immunodeficiency, graft rejection), making it a major therapeutic target for drug and cell therapies aimed at modulating immune function[3][4][5][6].

Other names

TCR:pMHC complexT cell receptor–peptide–MHC complexTCR–MHC–peptide complex

Blockade or modification of TCR-peptide–MHC interaction; Disruption or enhancement of signal transduction upon TCR engagement; Redirection of TCR specificity using engineered receptors (TCR-T cell therapies)