Abstract

Developing universal CARs with improved flexible targeting and controllable activities is urgently needed. While several studies have suggested the potential of CD16a in tandem with monoclonal antibodies to construct universal CAR T cells, the weak affinity between them is one of the limiting factors for efficacy. Herein, we systematically investigated the impact of Fc{gamma} receptor (Fc{gamma}R) affinity on CAR T cells properties by constructing universal CARs using Fc{gamma} receptors with different affinities for IgG1 antibodies, namely CD16a, CD32a, and CD64. We demonstrated that the activities of these universal CAR T cells on tumor cells could be redirected and regulated by IgG1 antibodies. In xenografted mice, 64CAR chimeric Jurkat cells with the highest affinity showed significant antitumor effects in combination with herceptin in the Her2 low expression U251 MG model. However, in the CD20 high expression Raji model, 64CAR caused excessive activation of CAR-T cells, which resulted in cytokine release syndrome (CRS) and the decline of antitumor activity, and 32CAR with a moderate affinity brought the best efficacy. Our work extended the knowledge about Fc{gamma}R-based universal CAR T cells and suggested that only the Fc{gamma}RCAR with an appropriate affinity can offer the optimal antitumor advantages of CAR T cells. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=82 SRC="FIGDIR/small/513394v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@1348ceorg.highwire.dtl.DTLVardef@10eb32org.highwire.dtl.DTLVardef@c12aeforg.highwire.dtl.DTLVardef@1e9c9ea_HPS_FORMAT_FIGEXP M_FIG C_FIG Universal CAR T cells based on Fc{gamma} receptors exhibit a specific tumor-killing effect. However, the affinities of Fc{gamma} receptors greatly influence the efficacy and adverse effects in vivo.