T-cell receptor recognizing a peptide-major histocompatibility complex (TCR)

The T-cell receptor (TCR) is a membrane-bound protein complex on T lymphocytes that recognizes antigens in the form of short peptides presented by major histocompatibility complex (MHC) molecules on antigen-presenting cells. The canonical TCR is made up of alpha and beta chains (occasionally gamma/delta) with hypervariable regions enabling diverse antigen recognition — the complementarity-determining regions (CDRs) contact both the MHC and the bound peptide. This interaction triggers intracellular signaling cascades via associated CD3 chains, leading to T cell activation and downstream adaptive immune responses. TCR-pMHC recognition is central to anti-infective, anti-tumor, and autoimmune functions. As a therapeutic target, the TCR–peptide-MHC axis is actively exploited in cellular immunotherapies, TCR mimic biologics, and cancer vaccine design. The diversity and specificity of the TCR repertoire provide an opportunity and a challenge for selective immune targeting and biomarker development. Notable safety concerns stem from unintended cross-reactivity, which may cause autoimmune side effects or tissue toxicity.

Other names

TCRT-cell antigen receptorT-cell receptor-pMHC complexTCR-pMHCAntigen receptor

Targeted TCR-T cell therapy: engineered TCR recognizes tumor-specific peptide-MHC and mediates tumor cell killing; Bispecific antibodies: redirect T cells to cancer cells presenting specific peptide-MHC; Immune checkpoint therapy (indirect modulation)