T-cell receptor:peptide–major histocompatibility complex complex (TCR:pMHC complex)

The T-cell receptor:peptide–major histocompatibility complex complex (TCR:pMHC complex) is a molecular assembly formed when a T-cell receptor (TCR) on the surface of a T lymphocyte binds to a specific antigenic peptide displayed by a major histocompatibility complex (MHC) molecule on an antigen-presenting cell[1][2][3][6]. MHC molecules (known as HLA in humans) present short peptide fragments derived from pathogens, tumours, or self-proteins, and are highly polymorphic to enable broad peptide presentation. The TCR, typically a heterodimer made of α and β chains, recognizes both the peptide and the MHC molecule with fine specificity, launching downstream immune signaling necessary for orchestrating adaptive immune responses[4][6]. The interaction between TCR, peptide, and MHC governs immune recognition, with disease relevance in cancer, infection, autoimmunity, and transplantation. TCR:pMHC specificity is foundational for immunotherapy approaches, notably for TCR-mimic antibodies and engineered TCR therapeutics, but presents challenges due to TCR cross-reactivity and risk of adverse immune effects[1][6].

Other names

TCR:pMHC complexT cell receptor:peptide–MHC complexT-cell receptor:peptide/MHC complexTCR–pMHC complexTCR–pMHC–CD4/CD8 complex

Targeted immune recognition (engineered TCRs or TCR-mimics bind tumour-specific pMHC)[6] T cell redirection (bispecifics linking TCR-pMHC and CD3 to activate T cells)[6] Immunomodulation via MHC blockade (rare, e.g., blocking peptide–MHC to suppress unwanted T cell activation)