T cell receptor–antigen–major histocompatibility complex (TCR–antigen–MHC complex)

The T cell receptor–antigen–major histocompatibility complex (TCR–antigen–MHC complex) is a multiprotein assembly composed of the highly variable T cell receptor (TCR) heterodimer, the peptide antigen, and the major histocompatibility complex (MHC) molecule that presents this antigen on antigen-presenting cells. The TCR, usually composed of α and β chains (occasionally γ and δ), uses its variable regions to specifically recognize processed antigens in the context of MHC, a process central to adaptive immunity. Interaction with the peptide–MHC complex (pMHC) triggers signal transduction via associated CD3 chains, leading to T cell activation, clonal expansion, and effector function. This complex is a pivotal focus for immunotherapy in cancer, infection, and autoimmune disease, with extensive research aimed at understanding its structure, specificity, and regulation, as well as therapeutic exploitation and safety challenges.

Other names

T cell receptor–antigen complexTCR–peptide–MHC complexpMHC–TCR complexTCR–MHC complex

Direct inhibition/blockade of TCR–MHC interaction (experimental); Activation of T cell responses via antigen-specific engagement; Restoration or augmentation of T cell function (e.g., in cancer therapy); Suppression of inappropriate activation (e.g., autoimmunity, transplant rejection); Modulation of signal transduction downstream of TCR/CD3 complex