title: Adoptive transfer of CD4+CD25+ regulatory cells combined with low-dose sirolimus and anti-thymocyte globulin delays acute rejection of renal allografts in Cynomolgus monkeys.
abstract: Although donor alloantigen specific Treg cells play an important role in transplant tolerance, therapeutic applications are limited by their low frequency. In this study, isolated Tregs from Cynomolgus monkeys were efficiently expanded by a co-culture system, and maintained suppressive function on the proliferation of CD4(+) effector cells in vitro. Adoptive transfer of expanded donor alloantigen specific Tregs without any immunosuppressants could prolong survival of MHC-mismatched allografts in Cynomolgus monkeys. To reach the feasibility of clinical transplantation, our objectives focused on whether exposure of monkey Tregs to immunosuppressants could preserve suppressive function in vitro and in vivo. The results showed that low-dose sirolimus selectively expanded Tregs, increased the expression of CD25(bright) and Foxp3 markers, and suppressed TCR- or allo-antigens induced CD4(+) T cell proliferation in vitro. In vivo, after pre-treated with anti-thymocyte globulin (ATG) for consecutive 3days, a 14-day therapy of adoptive infusion of donor alloantigen-specific Tregs combined with low-dose sirolimus delayed acute rejection of renal allografts in Cynomolgus monkeys, showing an MST of 48.5days as compared with those of untreated and sirolimus-treated monkeys (7days and 22days). The frequencies of CD4(+)CD25(bright) T cells were significantly elevated in mesenteric lymph nodes vs. those in inguino lymph nodes and peripheral blood. In summary, expanded donor alloantigen specific Tregs exposed to sirolimus can preserve inhibition in vitro and in vivo. Tregs are more resistant to sirolimus than other T cells. Expanded donor alloantigen specific Tregs combined with sirolimus and ATG prolongs renal allograft survival in monkeys, suggesting that sirolimus might be one of the best synergists for Tregs therapy.
authors.affiliation: Laboratory of Experimental Surgery, Research Centre, Center Hospitalier de l'Université de Montréal-Hôpital Notre-Dame, Department of Surgery, University of Montreal, Montréal, Québec, Canada.
authors.forename: Anlun
authors.initials: A
authors.lastname: Ma
authors.forename: Shijie
authors.initials: S
authors.lastname: Qi
authors.forename: Lijun
authors.initials: L
authors.lastname: Song
authors.forename: Yanxin
authors.initials: Y
authors.lastname: Hu
authors.forename: Hao
authors.initials: H
authors.lastname: Dun
authors.forename: Eric
authors.initials: E
authors.lastname: Massicotte
authors.forename: Martine
authors.initials: M
authors.lastname: Dupuis
authors.forename: Pierre
authors.initials: P
authors.lastname: Daloze
authors.forename: Huifang
authors.initials: H
authors.lastname: Chen
mesh_terms: D000208:Acute Disease; D019264:Adoptive Transfer; D000818:Animals; D000961:Antilymphocyte Serum / Q000008:administration & dosage*; D015704:CD4 Antigens / Q000096:biosynthesis; D002478:Cells, Cultured; D002985:Clinical Protocols; D003131:Combined Modality Therapy; D004357:Drug Synergism; D006084:Graft Rejection / Q000276:immunology / Q000517:prevention & control / Q000628:therapy*; D006085:Graft Survival / Q000187:drug effects; D053645:Interleukin-2 Receptor alpha Subunit / Q000096:biosynthesis; D007519:Isoantigens / Q000276:immunology; D016030:Kidney Transplantation; D008252:Macaca fascicularis; D020123:Sirolimus / Q000008:administration & dosage*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism* / Q000473:pathology / Q000637:transplantation
chemical_list: D000961:Antilymphocyte Serum; D015704:CD4 Antigens; D053645:Interleukin-2 Receptor alpha Subunit; D007519:Isoantigens; D020123:Sirolimus