Zhang, Gao, and Hu et al. addressed ways to enhance DC–T cell crosstalk in the TIME. BiDT, a bispecific DC–T cell engager (anti-Tim3–IFNα fusion), simultaneously bound Tim3 on exhausted TILs and activated DCs via the IFNAR receptor. In mouse models, BiDT resulted in potent antitumor activity, robust tumor specific memory, and synergized with anti-PD-L1 in an immune-cold tumor model. Mechanistically, BiDT depended on DCs and intratumoral, not LN, T cells, reactivated exhausted TIM3+ CD8+ TILs via anti-apoptotic Bcl-2 upregulation, and enhanced DC function via increased IL-2 production and B7/CD28 interactions. To address IFNα toxicity, an MMP-cleavable prodrug variant was generated.
Contributed by Katherine Turner
ABSTRACT: Tumor infiltrating T cells (TIL) are key players in the anti-tumor immune response. However, chronic exposure to tumor-derived antigens drives the differentiation into 'exhausted' TILs. Whether intratumoral dendritic cells (DC) can mitigate TILs exhaustion and maintain function is unclear. Here, we develop a bispecific DC-T cell engager (BiDT), consisting of an anti-TIM3-IFN fusion protein, and demonstrate that, in preclinical mouse tumor models, this engager simultaneously targets TIM3 on exhausted TILs and activates DCs via the IFNAR receptor. Mechanistically, BiDT reactivates exhausted TIM3(+)TILs by preventing apoptosis through increased Bcl-2 expression and enhances DC function to reactivate T cells via IL-2 signalling and co-stimulatory CD80/86-CD28 interactions within the tumor microenvironment. Finally, to mitigate IFN_-induced toxicity, we engineer a Pro-BiDT engager featuring a pro-IFN_ and report potent antitumor activity with reduced systemic toxicity. Thus, by bridging DC-T cells together, BiDT treatment enhances the critical communication pathways and cellular circuits necessary for effective anti-tumor immunity.
Author Info: (1) Institute for Data-Driven Tumor Immunology, Chongqing Medical University, Chongqing, China. xuhaozhang@cqmu.edu.cn. School of Basic Medical Sciences, Tsinghua University, Beiji
Author Info: (1) Institute for Data-Driven Tumor Immunology, Chongqing Medical University, Chongqing, China. xuhaozhang@cqmu.edu.cn. School of Basic Medical Sciences, Tsinghua University, Beijing, China. xuhaozhang@cqmu.edu.cn. Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China. xuhaozhang@cqmu.edu.cn. State Key Laboratory of Molecular oncology, Tsinghua University, Beijing, China. xuhaozhang@cqmu.edu.cn. (2) School of Basic Medical Sciences, Tsinghua University, Beijing, China. Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China. State Key Laboratory of Molecular oncology, Tsinghua University, Beijing, China. (3) School of Basic Medical Sciences, Tsinghua University, Beijing, China. State Key Laboratory of Molecular oncology, Tsinghua University, Beijing, China. (4) School of Basic Medical Sciences, Tsinghua University, Beijing, China. State Key Laboratory of Molecular oncology, Tsinghua University, Beijing, China. (5) School of Basic Medical Sciences, Tsinghua University, Beijing, China. Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, China. State Key Laboratory of Molecular oncology, Tsinghua University, Beijing, China. (6) School of Basic Medical Sciences, Tsinghua University, Beijing, China. China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China. (7) National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China. University of Chinese Academy of Sciences, Beijing, China. (8) Changping Laboratory, Beijing, China. (9) National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China. University of Chinese Academy of Sciences, Beijing, China. (10) Changping Laboratory, Beijing, China. (11) CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China. (12) Guangzhou National Laboratory, Bio-Island, Guangzhou, China. State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China. (13) School of Basic Medical Sciences, Tsinghua University, Beijing, China. wywang2022@tsinghua.edu.cn. State Key Laboratory of Molecular oncology, Tsinghua University, Beijing, China. wywang2022@tsinghua.edu.cn. (14) School of Basic Medical Sciences, Tsinghua University, Beijing, China. yangxinfu@tsinghua.edu.cn. State Key Laboratory of Molecular oncology, Tsinghua University, Beijing, China. yangxinfu@tsinghua.edu.cn. Changping Laboratory, Beijing, China. yangxinfu@tsinghua.edu.cn.
