IDR-induced CAR condensation improves the cytotoxicity of CAR-Ts against low-antigen cancers

Chimeric antigen receptor (CAR)-T cell therapies have shown remarkable efficacies for treating otherwise intractable cancers. However, current clinically approved CAR-T therapies are limited by low antigen sensitivity, impeding their efficacy against cancers with low antigen expression. Here, to address this issue, we engineered CARs targeting CD19, CD22 and HER2 by including intrinsically disordered regions (IDRs) that promote signaling condensation. We discovered that the CAR fused with an IDR from FUS, EWS or TAF15 promoted the formation of CAR-T conjugation with cancer targets, the mechanical strength of CAR-T synapses and membrane-proximal signaling, which led to an increased release of cytotoxic factors and a higher killing activity toward low-antigen-expressing cancer cells in vitro. Moreover, the FUS IDR CAR-T induced improved antitumor effects in both blood cancer and solid tumor models. No spontaneous activation in the absence of antigen was observed. Together, our work demonstrates IDRs as a new toolset for improving CAR-T function through inducing biomolecular condensation.