T cell receptor-CD3 complex and peptide-major histocompatibility complex (TCR-CD3:pMHC) (TCR-CD3:pMHC)

The T cell receptor (TCR)-CD3 complex and peptide-major histocompatibility complex (pMHC) interaction represents the fundamental recognition unit of the adaptive immune system [1, 3]. The TCR, in association with the CD3 signaling subunits, recognizes specific peptide fragments derived from intracellular proteins that are presented by MHC molecules on the surface of target cells [3]. This interaction is highly specific and is the basis for T cell-mediated surveillance of viral infections and malignancies [1]. In modern immunotherapy, this interface is targeted by TCR-engineered T cells (TCR-T) and bispecific T-cell engagers (e.g., ImmTACs) to redirect the immune system against tumor-specific intracellular antigens [2, 4]. By bypassing the need for surface protein expression, these therapies allow for the targeting of a much broader range of the proteome compared to traditional monoclonal antibodies [2]. The successful engagement of the TCR-CD3 complex with the pMHC triggers a cascade of intracellular signaling that leads to T cell activation, proliferation, and the release of cytotoxic granules to destroy the target cell [1]. This process results in the formation of an immunological synapse, concentrating effector molecules at the point of contact [3]. However, the high sensitivity of this interaction necessitates careful selection of peptide targets to avoid off-target toxicity against healthy tissues expressing similar peptides [4]. Therapeutic agents like Tebentafusp utilize this mechanism to treat uveal melanoma by targeting the gp100 peptide presented by HLA-A*02:01 [2].

Other names

TCR-pMHC complexTCR-CD3/pMHC interfaceT-cell receptor-antigen-MHC complexTCR-MHC-peptide complexImmunological synapse interface

Redirection of T-cell cytotoxicity toward cells presenting specific intracellular antigens via MHC; formation of a synthetic immunological synapse bridging effector T cells and target cells.