Testing various combinations, Fan et al. found that the administration of bispecific killer cell-engager (BiKE)-secreting CAR T cells alongside weekly injections of NK cells was optimal for achieving long-term control in murine hematologic tumor models. In a solid tumor model, NK cells co-administred with BiKE+ CAR T cells showed tumor parenchyma infiltration, whereas NK cells co-administred with BiKE- CAR T cells were primarily found in the peritumoral connective tissue. The simultaneous expression of a CD19-targeting CAR and EGFR-targeting BIKEs in T cell led to complete eradication of heterogeneous EGFR+CD19- and EGFR-CD19+ tumor cells in vivo.

Contributed by Ute Burkhardt

ABSTRACT: T cells and natural killer (NK) cells collaborate to maintain immune homeostasis. Current cancer immunotherapies predominantly rely on the individual application of these cells. Here we use bicistronic vectors to co-express chimeric antigen receptors (CARs) and secreted immune cell engagers (ICEs), leveraging the combined therapeutic potential of both effector cell types. After in vitro validation of immune cell engager secretion and function, various combinatorial approaches are systematically compared in mouse models, identifying a highly effective combination of bispecific killer cell engager (BiKE)-secreting CAR-T cells and NK cells. Beyond a simple combination of conventional CAR-T cells and NK cells, this strategy demonstrates superior efficacy in CD19(+) B cell leukaemia and lymphoma and EGFR(+) solid tumour models while reducing the dosage dependence on CAR-T cells. Moreover, CAR-T cells and BiKEs targeting distinct antigens exhibit suppression of tumour cells with heterogeneous antigen expression. These findings indicate that combining BiKE-secreting CAR-T cells and NK cells offers a promising strategy to combat tumour antigen heterogeneity and immune evasion.

Author Info: (1) Bone Marrow Transplantation Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China. Liangzhu Laboratory, Zhejiang University, Hangzhou,

Author Info: (1) Bone Marrow Transplantation Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China. Liangzhu Laboratory, Zhejiang University, Hangzhou, China. (2) Bone Marrow Transplantation Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China. Liangzhu Laboratory, Zhejiang University, Hangzhou, China. Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China. Institute of Hematology, Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Zhejiang University, Hangzhou, China. (3) Liangzhu Laboratory, Zhejiang University, Hangzhou, China. Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China. Institute of Hematology, Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Zhejiang University, Hangzhou, China. (4) Liangzhu Laboratory, Zhejiang University, Hangzhou, China. Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China. Institute of Hematology, Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Zhejiang University, Hangzhou, China. (5) Liangzhu Laboratory, Zhejiang University, Hangzhou, China. Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China. Institute of Hematology, Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Zhejiang University, Hangzhou, China. (6) Liangzhu Laboratory, Zhejiang University, Hangzhou, China. Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China. Institute of Hematology, Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Zhejiang University, Hangzhou, China. (7) School of Public Health, Zhejiang University School of Medicine, Hangzhou, China. (8) School of Public Health, Zhejiang University School of Medicine, Hangzhou, China. (9) Center for Cell Engineering and Immunology Program, Sloan Kettering Institute, New York, NY, USA. (10) Bone Marrow Transplantation Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China. huanghe@zju.edu.cn. Liangzhu Laboratory, Zhejiang University, Hangzhou, China. huanghe@zju.edu.cn. Institute of Hematology, Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Zhejiang University, Hangzhou, China. huanghe@zju.edu.cn. (11) Bone Marrow Transplantation Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China. sunj4@zju.edu.cn. Liangzhu Laboratory, Zhejiang University, Hangzhou, China. sunj4@zju.edu.cn. Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, China. sunj4@zju.edu.cn. Institute of Hematology, Zhejiang Engineering Laboratory for Stem Cell and Immunotherapy, Zhejiang University, Hangzhou, China. sunj4@zju.edu.cn.