Peptide–major histocompatibility complex on antigen-presenting cell and T-cell receptor on T cell (pMHC–TCR)

The *peptide–major histocompatibility complex (pMHC)–T-cell receptor (TCR) interface* represents the central molecular recognition event in adaptive immunity, whereby a TCR on the surface of a T cell specifically binds to a peptide bound to an MHC molecule displayed on an antigen-presenting cell (APC), such as a dendritic cell, macrophage, or B cell[2][5][6]. The peptide is generally derived from processed foreign or self-proteins; the MHC is either class I (recognized by cytotoxic T cells) or class II (by helper T cells). This molecular interaction is essential for T-cell activation, selection, and immune surveillance, and triggers intracellular signaling cascades through the CD3 complex, ultimately determining the specificity and outcome of immune responses[1][4][6][7]. The TCR–pMHC interaction is the basis of T-cell antigen specificity and underlies pathological outcomes in autoimmunity, cancer, infection, and transplantation. Note: This query points to an *interaction* or multi-protein complex, not a single canonical molecular target. Both the T-cell receptor and the peptide–MHC complex (of diverse allelic forms) are individually subject to therapeutic targeting and structural definition, but "Peptide-MHC complexes on APCs and T-cell receptors on T-cells" describes a recognition event, not a single molecular entity, so use with care for structured databases. For detailed, structured use, it is recommended to describe T-cell receptor (TCR) and peptide–MHC complex (pMHC) separately, then also annotate their interaction or interface as a higher-order immunological target[1][5][6].

Other names

pMHC–TCR interactionT-cell receptor–peptide–MHC complexTCR–MHC–peptide complex

Blockade of TCR–pMHC binding (theoretical and experimental agents); Modulation of TCR downstream signaling (e.g., calcineurin inhibitors block signal transduction); Immune checkpoint modulation (downstream pathway intervention).