Split-design approach enhances the therapeutic efficacy of ligand-based CAR-T cells against multiple B-cell malignancies

To address immune escape, multi-specific CAR-T-cell strategies use natural ligands that specifically bind multiple receptors on malignant cells. In this context, we propose a split CAR design comprising a universal receptor expressed on T cells and ligand-based switch molecules, which preserves the natural trimeric structure of ligands like APRIL and BAFF. Following optimization of the hinges and switch labeling sites, the split-design CAR-T cells ensure the native conformation of ligands, facilitating the optimal formation of immune synapses between target cancer cells and CAR-T cells. Our CAR-T-cell strategy demonstrates antitumor activities against various B-cell malignancy models in female mice, potentially preventing immune escape following conventional CAR-T-cell therapies in the case of antigen loss or switching. This ligand-based split CAR design introduces an idea for optimizing CAR recognition, enhancing efficacy and potentially improving safety in clinical translation, and may be broadly applicable to cellular therapies based on natural receptors or ligands. A switchable CAR-T cell platform comprises a universal receptor expressed on T cells and tumor-targeting adapter molecules. Here the authors propose an APRIL- and BAFF-based switchable CAR strategy for ligand-mediated CAR-T-cell activation, showing anti-tumor activity in models of B-cell malignancies.