T cell receptor-Major Histocompatibility Complex (TCR-MHC) (TCR-MHC)

The T cell receptor-Major Histocompatibility Complex (TCR-MHC) is a fundamental molecular interaction required for the initiation of the adaptive immune response (Janeway's Immunobiology, 9th Ed). The TCR, located on the surface of T lymphocytes, recognizes specific antigenic peptides presented by MHC molecules (Human Leukocyte Antigens/HLA in humans) on the surface of antigen-presenting cells or malignant cells (UniProt, P01889). This interaction is highly specific and determines the T cell's ability to distinguish between self and non-self or altered-self (cancer) antigens (PubMed: 28250458). In therapeutic contexts, this complex is targeted by engineered TCR-T cell therapies, such as Afamitresgene autoleucel, which targets MAGE-A4 (FDA, 2024), and by bispecific molecules like Tebentafusp, which targets gp100 (PubMed: 34554482). Dysregulation of the TCR-MHC interaction is central to the pathogenesis of autoimmune diseases, where self-antigens are incorrectly recognized, and in cancer evasion, where tumors downregulate MHC to avoid detection (Nature Reviews Immunology, 2021). Modulating this interaction offers a powerful pathway for treating malignancies and immune-mediated disorders, though it carries significant risks. These include cytokine release syndrome (CRS) and on-target off-tumor toxicity, where the therapy recognizes similar peptides in healthy tissues (StatPearls, NBK545245). Successful targeting often requires precise patient selection based on HLA typing and antigen expression levels (PubMed: 31110339).

Other names

TCR-pMHC complexT-cell receptor-peptide-MHC complexTCR-HLA complexAntigen-specific T-cell receptor complex

Drugs targeting the TCR-MHC complex function by redirecting T-cells to specific peptide-MHC targets via bispecific fusion proteins (ImmTACs), engineering T-cells with high-affinity TCRs (TCR-T therapy), or modulating the TCR-CD3 complex to suppress or activate immune responses (PubMed: 31110339).