T cell receptor redirected T cells in tumour immunotherapy

Adoptive T cell transfer has revolutionized the field of cancer immunotherapy due to the specificity and effectiveness, particularly for haematological malignancies. However, challenges still remain in achieving a satisfactory therapeutic response in solid tumours. Additionally, the potential safety concerns such as risk of lethal off-tissue effects as well as virus transduction-mediated random gene integration, all indicate a major need to optimize T cell engineering strategies for safer and more effective T cell therapeutics. In this study, the successful establishment of CRISPR-mediated non-viral orthotopic TCR replacement system preserved the best T cell functionality in recipient cells. Transcriptomic strategies identified the most activated and effector-like T cells in peripheral blood to have a preferential selective advantage for T cell engineering and long-term survival. In addition, the in vitro T cell manipulation and expansion selectively upregulated NK inhibitory receptors in those surviving T cells. Moreover, we also characterised the TCRs of the same specificity but different functional avidity in tumour control and showed that a CD8-independent high functional avidity TCR was more potent in tumour control in part by redirecting CD4+ T cells towards MHC-I restricted tumour epitopes. In addition, in investigating alternative T cell engineering strategies to improve TCR-T cell function, we demonstrated the feasibility and effectiveness of manipulating unconventional T cells for T cell therapies and developed novel engineering designs in controlling TCR-T cell function. Collectively, this study defined optimized T cell engineering strategies and investigated the underlying mechanisms including T cell preferential selection, TCR selection in tumour control and alternative T cell engineering strategies for improved TCR-T cell functions. A comprehensive understanding of these factors will ultimately guide us in designing the most effective T cell engineering strategies for future translational clinical applications.