Major histocompatibility complex class I – T-cell receptor complex (MHC I-TCR complex) (MHC I-TCR complex)

The Major histocompatibility complex class I – T-cell receptor (MHC I-TCR) complex is the fundamental molecular assembly required for the recognition of intracellular antigens by CD8+ cytotoxic T cells (StatPearls, 2023). This complex consists of a peptide-loaded MHC class I molecule on an antigen-presenting cell or target cell interacting with a specific T-cell receptor (TCR) on a CD8+ T cell, a process further stabilized by the CD8 co-receptor (UniProt, 2024). The interaction is highly specific, as the TCR must recognize both the polymorphic MHC molecule and the specific 8-11 amino acid peptide nestled within its binding groove (Nature Reviews Immunology, 2021). This recognition event triggers a signaling cascade through the CD3 complex, leading to the activation of the T cell and the subsequent destruction of the target cell via the release of perforin and granzymes (PubMed, 2022). In the context of disease, the MHC I-TCR complex is critical for clearing viral infections and eliminating malignant cells that present neoantigens or overexpressed self-antigens. Therapeutic strategies targeting this complex include TCR-engineered T-cell (TCR-T) therapies and bispecific T-cell engagers, such as Tebentafusp, which are designed to bypass natural immune tolerance and direct a potent immune response against specific tumor-associated pMHC targets (FDA, 2022).

Other names

pMHC-TCR complexPeptide-MHC class I-TCR complexHLA-TCR complexAntigen-MHC-TCR synapse

TCR-mediated T-cell activation, Cytotoxic T-lymphocyte induction, Antigen-specific cell lysis, and T-cell redirection.