Background Infusion of recipient regulatory T cells (Treg) promotes durable mixed hematopoietic chimerism and allograft tolerance in mice receiving allogeneic BMT with minimal conditioning. We applied this strategy in a Cynomolgus macaque model. Methods CD4+CD25high Treg that were polyclonally expanded in culture were highly suppressive in vitro and maintained high expression of FoxP3. Eight monkeys underwent nonmyeloablative conditioning and MHC-mismatched BMT with or without Treg infusion. Renal transplantation (from the same BMT donor) was performed 4 months post-BMT without immunosuppression to assess for robust donor-specific tolerance. Results Transient mixed chimerism, without significant T cell chimerism, was achieved in the animals that received BMT without Treg (N=3). In contrast, the 2 of 5 recipients of Treg + BMT that were evaluable displayed chimerism in all lineages, including T cells, for up to 335 days post-BMT. Importantly, in the animal that survived long-term, >90% of donor T cells were CD45RA+CD31+, suggesting they were new thymic emigrants. In this animal, the delayed (to 4 months) donor kidney graft was accepted >294 days without immunosuppression, whereas non-Treg BMT recipients rejected delayed donor kidneys within 3-4 weeks. Early cytomegalovirus reactivation and treatment was associated with early failure of chimerism, regardless of Treg administration. Conclusions Our studies provide proof-of-principle that, in the absence of early CMV reactivation (and BM-toxic antiviral therapy), co-transplantation of host Treg can promote prolonged and high levels of multilineage allogeneic chimerism and robust tolerance to the donor.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.