Modular cell line for scalable and rapid in vitro evaluation of chimeric antigen receptors

The development of novel Chimeric Antigen Receptor T-cell (CAR-T-cell) products relies on continuous in vitro testing of new antigen/antibody pairs, as well as the modification of the CAR structure and composition. Once Tumor-Associated Antigens (TAA) have been chosen and proven to be specific, and before the first in vivo studies, these CAR compositions must be extensively validated in vitro. Conventional in vitro tests rely on TAA-expressing immortalized cell lines or immortalized cell lines derivatives engineered to stably express the antigen of interest, making this type of model not fully scalable when it comes to multiple TAA/antibody pairs. Therefore, there is a need for a representative, scalable model for preclinical assessment. Here, we introduce a novel model cell line-based approach that can be easily adapted for different experiments by anchoring ALFA-tagged proteins on the cell surface using an anti-ALFA-tag membrane single-domain antibody. This modular multi-component system has the potential to reduce the novel CAR in vitro evaluation procedures from months to weeks.