Introducing arginine residues into scFv in CAR-T cells shows promising antitumor effects

Current research investigating chimeric antigen receptor (CAR)-T cell therapeutics indicates that CAR properties other than intracellular signaling systems, such as high association rate constants and enhanced self-interaction of the antigen-binding domain (ABD), elicit enhanced therapeutic efficacy and are key factors for CAR-T candidates. However, rational strategies to achieve these features are to be established. To develop novel CAR-T cells with these characteristics, ABD was engineered by introducing several arginine residues into the light-chain framework region-3 of the single-chain fragment variable. The mutant CAR-T cells exhibited a higher cell-killing efficacy than that of wild-type cells and superior antitumor effects in mice, prolonged persistence in vivo, and decreased interferon-γ secretion. RNA sequencing revealed differential gene expression profiles between the mutant and wild-type CAR-T cells before and after antigen stimulation. In conclusion, we proposed a design strategy to generate CAR-T cells with high therapeutic efficacy by modulating CAR properties using an arginine cluster.