Functional and structural analysis of KK-LC-1-specific T cell receptors from patients with lung Cancer for immunotherapy

Adoptive T-cell receptor (TCR)-engineered T cell therapy is a promising approach for cancer immunotherapy, particularly for cancer/testis antigens such as KK-LC-1. We evaluated four KK-LC-1 epitope-specific TCRs restricted by Human Leukocyte Antigen (HLA)-B*15:01, including three identified by our group and one previously reported. Their properties were characterised using TCRαβ-transduced γδT and Jurkat cells through functional analyses, including IFN-γ production, activation marker expression, cytotoxicity, TCR signalling, and T cell-target cell interactions, complemented by molecular dynamics simulations. One TCR exhibited superior performance, with the highest IFN-γ production, activation marker expression, and cytotoxicity, sustaining robust TCR signalling at low antigen levels and enhancing T cell-target interactions. Molecular dynamics simulations revealed that it exhibited a high binding affinity and stable interface, characterised by hydrogen bonds evenly distributed across the peptide and HLA α1/α2 helices, likely contributing to the conformational stability of the TCR-pMHC complex. These findings suggest that the functional superiority of this TCR is attributable to its structurally balanced and stable engagement with the pMHC complex. This study highlights the structural basis of TCR efficacy and provides a practical framework for optimising TCR selection for adoptive immunotherapy.