title: Role of double-negative regulatory T cells in long-term cardiac xenograft survival.
abstract: A novel subset of CD3(+)CD4(-)CD8(-) (double negative; DN) regulatory T cells has recently been shown to induce donor-specific skin allograft acceptance following donor lymphocyte infusion (DLI). In this study, we investigated the effect of DLI on rat to mouse cardiac xenotransplant survival and the ability of DN T cells to regulate xenoreactive T cells. B6 mice were given either DLI from Lewis rats, a short course of depleting anti-CD4 mAb, both DLI and anti-CD4 treatment together, or left untreated. DLI alone did not prolong graft survival when compared with untreated controls. Although anti-CD4-depleting mAb alone significantly prolonged graft survival, grafts were eventually rejected by all recipients. However, the combination of DLI and anti-CD4 treatment induced permanent cardiac xenograft survival. We demonstrate that recipients given both DLI and anti-CD4 treatment had a significant increase in the total number of DN T cells in their spleens when compared with all other treatment groups. Furthermore, DN T cells harvested from the spleens of DLI plus anti-CD4-treated mice could dose-dependently inhibit the proliferation of syngeneic antidonor T cells. Suppression mediated by these DN T cells was specific for antidonor T cells as T cells stimulated by third-party Ags were not suppressed. These results demonstrate for the first time that a combination of pretransplant DLI and anti-CD4-depleting mAb can induce permanent survival of rat to mouse cardiac xenografts and that DN T regulatory cells play an important role in preventing long-term concordant xenograft rejection through the specific suppression of antidonor T cells.
authors.affiliation: Department of Laboratory Medicine and Pathobiology, Multi Organ Transplantation Program, Toronto General Research Institute, University Health Network, University of Toronto, Toronto, Ontario, M5G 2C4 Canada.
authors.forename: Wenhao
authors.initials: W
authors.lastname: Chen
authors.forename: Megan S
authors.initials: MS
authors.lastname: Ford
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Young
authors.forename: Myron I
authors.initials: MI
authors.lastname: Cybulsky
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage; D000941:Antigens / Q000378:metabolism; D000954:Antigens, Surface; D017252:CD3 Complex / Q000096:biosynthesis; D015704:CD4 Antigens / Q000276:immunology / Q000378:metabolism*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D016827:CD8 Antigens / Q000378:metabolism*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002455:Cell Division / Q000235:genetics / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D006082:Graft Enhancement, Immunologic / Q000379:methods*; D006085:Graft Survival / Q000235:genetics / Q000276:immunology; D016027:Heart Transplantation / Q000276:immunology*; D007108:Immune Tolerance / Q000235:genetics; D007165:Immunosuppression Therapy; D007274:Injections, Intraperitoneal; D007399:Interphase / Q000276:immunology; D037181:Lectins, C-Type; D008213:Lymphocyte Activation / Q000235:genetics / Q000276:immunology; D017710:Lymphocyte Transfusion; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D055651:NK Cell Lectin-Like Receptor Subfamily B; D011506:Proteins / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D011920:Rats, Inbred WF; D013154:Spleen / Q000166:cytology / Q000378:metabolism / Q000637:transplantation; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D019172:Transplantation Conditioning; D014183:Transplantation, Heterologous / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000941:Antigens; D000954:Antigens, Surface; D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens; D018984:Epitopes, T-Lymphocyte; D037181:Lectins, C-Type; D055651:NK Cell Lectin-Like Receptor Subfamily B; D011506:Proteins