T cell receptor–Major Histocompatibility Complex–peptide complex (TCR-MHC-p)

The T cell receptor (TCR) recognition of the MHC–tumor antigen complex represents the fundamental interaction of the adaptive immune system's cellular arm. This process occurs when a TCR on a T lymphocyte binds to a specific peptide fragment (tumor antigen) displayed within the groove of a Major Histocompatibility Complex (MHC) molecule on the surface of a dendritic cell or tumor cell. In the context of dendritic cells, this interaction is crucial for 'priming' or activating naive T cells, which then proliferate and seek out tumor cells expressing the same antigen-MHC combination. This recognition event is highly specific, determined by the unique amino acid sequence of both the TCR and the peptide-MHC complex. Therapeutic strategies targeting this interaction include TCR-engineered T cell (TCR-T) therapies, soluble TCR bispecifics, and cancer vaccines designed to enhance the presentation of these complexes. By modulating this recognition, clinicians aim to overcome tumor immune evasion and direct a potent, specific immune response against malignant tissues.

Other names

TCR-pMHC complexAntigen-MHC complexT cell receptor-antigen recognitionpMHC-TCR interactionPeptide-MHC-TCR ternary complex

The T cell receptor (TCR) specifically binds to a peptide antigen presented by the Major Histocompatibility Complex (MHC) on the surface of an antigen-presenting cell, such as a dendritic cell. This binding event, often stabilized by co-receptors like CD4 or CD8, induces a conformational change in the TCR-CD3 complex, leading to the phosphorylation of immunoreceptor tyrosine-based activation motifs (ITAMs) and subsequent T cell proliferation, cytokine production, and cytotoxic activity against cells expressing the target antigen.