Dual CAR-T cells targeting CD19 and CD37 are effective in target antigen loss B cell tumor models.

Chimeric antigen receptor T (CAR-T) cells targeting multiple antigens, may reduce the risk of immune escape following the loss of the target antigen and further increase the efficacy of treatment. We developed dual-targeting CAR-T cells that target CD19 and CD37 antigens and evaluated their antitumor effects. CD19/CD37 dual CAR-T cells were generated using co-transduction and simultaneous gene transfer of two types of lentiviral vectors transferring CD19CAR or CD37CAR genes, including the intracellular domains of CD28 and CD3ζ signaling domains. These dual CAR-T cells contained three fractions: CD19/CD37 bispecific CAR-T cells, single CD19CAR-T cells, and single CD37CAR-T cells. In the functional evaluation of CAR-T cells in vitro, CD19/CD37 dual CAR-T cells showed adequate proliferation and cytokine production in response to CD19 and CD37 antigen stimulation alone or in combination. Evaluation of intracellular signaling revealed that dual CAR-T cell-mediated signals were comparable to single CAR-T cells in response to CD19 and CD37 positive B Cell tumors. Although the cytotoxicity of CD19/CD37 dual CAR-T cells in both CD19 and CD37 positive B cell tumors was similar to that of single CD19 and CD37CAR-T cells, against CD19 and CD37 antigen-heterogeneous tumor, dual CAR-T cells demonstrated significantly superior tumor lysis compared with single CAR-T cells. Furthermore, CD19/CD37 dual CAR-T cells effectively suppressed antigen-heterogeneous Raji cells in a xenograft mouse model. Collectively, these results suggest that CD19/CD37 dual CAR-T cells may be effective target-antigen-loss B-cell tumor models in vitro and in vivo, which represents a promising treatment for patients with relapsed/refractory B-cell malignancies.