Advances in preclinical TCR characterization: leveraging cell avidity to identify functional TCRs

Abstract T-cell therapy has emerged as an effective approach for treating viral infections and cancers. However, a significant challenge is the selection of T-cell receptors (TCRs) that exhibit the desired functionality. Conventionally in vitro techniques, such as peptide sensitivity measurements and cytotoxicity assays, provide valuable insights into TCR potency but are labor-intensive. In contrast, measuring ligand binding properties (z-Movi technology) could provide an accelerated processing while showing robust correlations with T-cell functions. In this study, we assessed whether cell avidity can predict functionality also in the context of TCR-engineered T cells. To this end, we developed a flexible system for TCR re-expression by generating a Jurkat-derived T cell clone lacking TCR and CD3 expression through CRISPR-Cas9-mediated TRBC knockout. The knockin of a transgenic TCR into the TRAC locus restored TCR/CD3 expression, allowing for CD3-based purification of TCR-engineered T cells. Subsequently, we characterized these engineered cell lines by functional readouts, and assessment of binding properties through the z-Movi technology. Our findings revealed a strong correlation between the cell avidities and functional sensitivities of Jurkat TCR-T cells. Altogether, by integrating cell avidity measurements with our versatile T cell engineering platform, we established an accelerated system for enhancing the in vitro selection of clinically relevant TCRs.