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

The **major histocompatibility complex-peptide complex and T-cell receptor** is the interface through which T lymphocytes specifically recognize antigenic peptides presented on the surface of other cells by major histocompatibility complex (MHC) molecules[3][4][6]. The complex consists of the peptide bound in the groove of an MHC molecule and the T-cell receptor (TCR) on the T cell membrane, which physically contacts both the peptide and the MHC to trigger T cell activation[1][2][6]. The TCR is a heterodimer, usually comprising alpha and beta chains, that recognizes fragments of antigen as bound to MHC molecules on antigen-presenting cells, initiating adaptive immune responses[3][6]. The specificity and structure of the TCR-pMHC complex is central to T-cell mediated immune surveillance, self/non-self discrimination, cancer immunity, and autoimmunity[5][6][7]. Structural determinants include three complementarity-determining regions (CDRs) on each TCR chain, which interact with both the MHC and the peptide, forming a highly selective yet degenerate recognition interface[4][6]. Engineering and modulation of TCR:pMHC interactions underpin key immunotherapies and present major safety and efficacy challenges, including off-target toxicity and immune escape[6].

Other names

MHC-peptide complexTCR-pMHC complexPeptide-major histocompatibility complex and T-cell receptorTCR:pMHCMHC-TCR complexpMHC-TCR complex

Blocking inhibitory checkpoint pathways to enhance TCR signaling Engineering T cells with specific TCRs for adoptive cell therapy Targeting MHC-peptide complexes with antibodies to modulate immune recognition