Xu et al. identified optimal and reproducible culture and cytokine conditions to create universal, human iPSC-derived DCs lacking HLA (B2m/CTIIA KO) and with a CCR7+ migratory DC phenotype. An exosome-inspired process with tumor cell vesicles was used to cross-dress these DCs with peptide:MHC complexes from tumor cells. Cross-dressing promoted antigen presentation and resistance to “non-self” killing by NK cells. With cell lines in vitro and in vivo, the cross-dressed DCs enhanced T cell cytotoxicity and tumor control. Personal cross-dressed vaccines in AML and ovarian cancer were cytolytic in vitro. PD-L1/2 knockout improved activity.

Contributed by Ed Fritsch

ABSTRACT: Autologous-derived dendritic cells (DCs) are a promising source for cell-based cancer vaccines. However, their therapeutic potential is challenged by the number and quality produced and the diversity of antigens presented. To address these limitations, we present an approach that involves differentiating universal MHC-deficient human-induced pluripotent stem cells (hiPSCs) into CCR7(+) migratory DCs. These DCs are subsequently "dressed" with the full repertoire of MHC-antigen complexes derived from tumor cell membranes, transforming an allogeneic substrate into a personalized cancer vaccine product. The resulting "TumorDressed" DCs effectively activate T cells against tumor antigens. Their function is diminished when CD80/86 is deleted but significantly enhanced by the loss of PD-L1/2. PD-L1/2-null TumorDressed DCs demonstrate robust priming of anti-tumor T cell-mediated cytotoxicity both in vitro and in vivo, including against primary hematologic and solid tumors with matching patient T cells. These findings provide proof of concept for a universal, scalable, adaptable, and off-the-shelf DC cancer vaccine platform.

Author Info: (1) Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, San Francisco (UCSF), San Francisco, CA, USA; Department of Urology, Univ ersity of California, San Francisco (UCSF), San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA. (2) Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, San Francisco (UCSF), San Francisco, CA, USA; Department of Urology, University of California, San Francisco (UCSF), San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA. (3) Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, San Francisco (UCSF), San Francisco, CA, USA; Department of Urology, University of California, San Francisco (UCSF), San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA. (4) Division of Hematology and Oncology, Department of Medicine, University of California, San Francisco (UCSF), San Francisco, CA, USA. (5) Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, San Francisco (UCSF), San Francisco, CA, USA; Department of Urology, University of California, San Francisco (UCSF), San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA. (6) Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, San Francisco (UCSF), San Francisco, CA, USA; Department of Urology, University of California, San Francisco (UCSF), San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA. (7) Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan. (8) Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, San Francisco (UCSF), San Francisco, CA, USA; Department of Urology, University of California, San Francisco (UCSF), San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA. (9) AIVITA Biomedical, Irvine, CA, USA. (10) Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan. (11) Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA; Division of Hematology and Oncology, Department of Medicine, University of California, San Francisco (UCSF), San Francisco, CA, USA. (12) AIVITA Biomedical, Irvine, CA, USA. (13) AIVITA Biomedical, Irvine, CA, USA. (14) Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA; Division of Hematology and Oncology, Department of Medicine, University of California, San Francisco (UCSF), San Francisco, CA, USA. (15) Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan. (16) Division of Hematology and Oncology, Department of Medicine, University of California, San Francisco (UCSF), San Francisco, CA, USA. (17) Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, San Francisco (UCSF), San Francisco, CA, USA; Department of Urology, University of California, San Francisco (UCSF), San Francisco, CA, USA; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco (UCSF), San Francisco, CA, USA. Electronic address: robert.blelloch@ucsf.edu.