Lease of EVs per cell, high purity EVs.OF11.Prolongation of allograft survival by way of donor MHC chimerism induced by CD117/c-KIT Proteins site extracellular vesicles Bruno Adonai Gonzalez Nolascoa, Mengchuan Wanga, William Orenta, Aurore Prunevieillea, Jane Oa, Kaitlan Ahrensa, Joren C Madsenb and Gilles BenichouaISEV2019 ABSTRACT BOOKa Division of Surgery, Center for Transplantation Sciences, Massachusetts Basic Hospital and Harvard Medical School, Boston, USA; bDepartment of Surgery, Center for Transplantation Sciences and Division of Cardiac Surgery, Massachusetts Basic Hospital and Harvard Medical School, Boston, USAOF11.Proteomic and transcriptomic characterization of exosomes-mimetic nanovesicles reveals their relevance as a therapeutic delivery program Amirmohammad Nasiri Kenaria, Kenneth Kastaniegaardb, Mitch C. Shambrooka, David Greeninga, Allan Stensballeb, Lesley Chenga and Andrew HillcaIntroduction: Reaching robust and durable host immune tolerance of allogeneic transplants is definitely the ultimate target in clinical transplantation. Mixed chimerism induced by means of donor bone marrow transplantation and host non-myeloablative conditioning has reliably accomplished tolerance of allogeneic organ transplants in mice and humans. Tolerance within this model is believed to rely primarily around the presentation of donor MHC molecules in the host’s thymus. Within this study, we investigated no matter if donor MHC chimerism could be accomplished by means of donor extracellular vesicles (EVs) injections and subsequent cross-dressing of recipient cells inside the host’s thymus. Techniques: Conditioned SJL (CD45.1+, H2-Ks+) recipient mice received a single IV dose of purified bone marrow derived exosome-enriched EVs (BM-EVs) isolated from C57BL/6 (CD45.2+, H2-Kb+) donors by way of sequential centrifugation or making use of a commercially obtainable exosome isolation kit. Nanoparticle tracking showed vesicles of approximately 100nm in size inside the BM-EVs preparation and Western Blot showed the presence of MHCI. Image flow cytometry was utilized to detect the presence of cross-dressed cells from day 10 by way of 100 following exosome injection. For NHP research, MHC class I H38+ BM-EVs have been injected into a H38- conditioned cynomolgus macaque before a combined heart and kidney TREM-1/CD354 Proteins Species transplant. PBMCs, thymus, spleen and mesenteric lymph nodes have been collected for image flow cytometry. Outcomes: Intravenous injection of BM-EVs into conditioned mice resulted within the presentation of donor MHC and CD45.1 molecules by host’s thymic and splenic cells. Similarly, H38+cross-dressed cells had been detected at D33 following exosome injection in all the NHP recipient tissues collected. In mice, donor but not syngeneic or third-party BM-EVs significantly prolonged skin allograft survival (median survival = 17 VS 11 days, p 0.001). Summary/Conclusion: These final results show that delivery of donor-derived extracellular vesicles can induce donor MHC chimerism by means of cross-dressing of recipient APCs with allogeneic MHC molecules in the host’s thymus. This suggests that donor EVs may very well be made use of in spot of bone marrow cells to induce chimerism and allograft survival with minimal conditioning and no risk of graft versus host disease (GVHD). Funding: NIH R01DK115618.bDepartment of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia; Division of Health Science and Technology, Faculty of Medicine, Aalborg University, Denmark, Aalborg, Denmark; cThe Division of Biochemistry and Genetics, La Trobe Institute for Molec.