Fu et al. showed that an i.v. or s.c. Tim3-targeted vaccine, generated by conjugating antigens to anti-Tim3 antibodies, delivered antigens to both cDC1s and cDC2s and elicited robust and durable CD8+ T cell responses. This Tim3-targeted vaccine restored cross-priming in both β-catenin-driven DC dysfunction and established tumor-mediated immunosuppression across different tumor settings. In Batf3-/- mice lacking cDC1s, CD8+ T cell priming and tumor control were reduced, but not eliminated. A single dose of anti-Tim3 neoantigen vaccine eradicated large established solid tumors and generated memory responses in a CD8+ T cell-dependent manner.
Contributed by Shishir Pant
ABSTRACT: Conventional type 1 dendritic cells (cDC1s) are specialized for cross-presenting tumor antigens and determining the efficacy of immunotherapies, including immune checkpoint blockade and adoptive cell therapy. However, their rarity and tumor-induced dysfunction severely limit CD8 T cell priming and represent a central bottleneck to therapeutic efficacy. While strategies such as anti-DEC-205-mediated antigen delivery and Flt3L-driven DC expansion can enhance host DC function, their reliance on functional cDC1s remains a significant constraint. We developed Tim-3-targeted vaccines by conjugating tumor antigens or neoantigens to anti-Tim-3 antibodies. These vaccines delivered antigens to both cDC1s and cDC2s, and elicited robust, durable CD8 T cell responses. Remarkably, Tim-3-targeted vaccines endowed cDC2s with efficient cross-presentation capacity that matched that of cDC1s. In tumor-bearing mice or in CD11c-_-catenin(active) mice, which model _-catenin-driven DC dysfunction, Tim-3-targeted vaccination restored cross-priming and counteracted tumor- and DC-mediated immunosuppression. In Batf3(-/-) mice lacking cDC1s, anti-Tim-3-based vaccines still elicited significant CD8 T cell cross-priming and tumor control-albeit both were reduced compared to wild-type mice- demonstrating that cDC1s contribute to but are not essential for Tim-3-targeted vaccine-induced CD8 T cell priming and anti-tumor efficacy. Strikingly, a single dose of anti-Tim-3-neoantigen vaccination eradicated large established MC38 tumors in a CD8 T cell-dependent manner. Together, these data identify Tim-3-targeted vaccines as a next-generation cancer vaccine platform that broadens DC engagement, reduces reliance on cDC1s, and overcomes tumor- and DC-mediated immunosuppression, addressing key limitations of current DC-based cancer vaccines.
Author Info: (1) Center for Cutaneous Biology and Immunology, Department of Dermatology, Henry Ford Health, Detroit, MI 48202. Immunology Program, Henry Ford Cancer Institute, Henry Ford Health
Author Info: (1) Center for Cutaneous Biology and Immunology, Department of Dermatology, Henry Ford Health, Detroit, MI 48202. Immunology Program, Henry Ford Cancer Institute, Henry Ford Health, Detroit, MI Department of Medicine, College of Human Medicine, Michigan State University, East Lansing, MI 48824. (2) Department of Computer Science and Engineering, School of Engineering and Computer Science, Oakland University, Rochester, MI 48309. (3) Institute for Molecular Medicine and Research Center for Immunotherapy, University Medical Center of the Johannes Gutenberg-University, Mainz 55131, Germany. (4) Department of Biochemistry and Biophysics, School of Medicine, University of California, San Francisco, CA 94143. Parker Institute for Cancer Immunotherapy, San Francisco, CA 94129. (5) Center for Cutaneous Biology and Immunology, Department of Dermatology, Henry Ford Health, Detroit, MI 48202. Immunology Program, Henry Ford Cancer Institute, Henry Ford Health, Detroit, MI Department of Medicine, College of Human Medicine, Michigan State University, East Lansing, MI 48824.
