Major histocompatibility complex–peptide complex and T-cell receptor (MHC–peptide complex and TCR)

Major histocompatibility complex (MHC) molecules on the surface of antigen-presenting cells (such as dendritic cells and B cells) bind and present peptide antigens, derived from pathogens or altered self-proteins, within a peptide-binding groove[1][3][8]. T-cell receptors (TCR) on T lymphocytes specifically recognize these peptide–MHC (pMHC) complexes, launching antigen-specific T cell activation and subsequent adaptive immune responses[4][5]. The interaction’s specificity is determined by the structure of both the MHC molecule and the displayed peptide, as well as by the highly variable TCR sequence on each T cell[3][7]. This interface underlies the specificity, diversity, and discrimination of self/nonself essential to immune surveillance, pathogen defense, immunotherapy, and autoimmunity. Approaches targeting or manipulating this interaction form the basis for cancer immunotherapies, infectious disease vaccines, and therapies targeting autoimmune disease[4][6][9].

Other names

pMHC–TCR complexPeptide–MHC–TCR interfaceTCR–peptide/MHC interactionT cell immunological synapse

Blocking/inhibiting co-receptors or checkpoint proteins that modulate the TCR–pMHC signal (e.g., anti-PD-1 antibodies prevent inhibitory signaling after TCR engagement) Engineered TCR therapies: redirect or enhance T cell specificity for particular antigen–MHC complexes Modulation of antigen presentation or TCR signaling to enhance/depress immune activation