title: Donor lymphocyte infusion induces long-term donor-specific cardiac xenograft survival through activation of recipient double-negative regulatory T cells.
abstract: Previous studies have shown that pretransplant donor lymphocyte infusion (DLI) can enhance xenograft survival. However, the mechanism by which DLI induces xenograft survival remains obscure. Using T cell subset-deficient mice as recipients we show that CD4+, but not CD8+, T cells are necessary to mediate the rejection of concordant cardiac xenografts. Adoptive transfer of naive CD4+ T cells induces rejection of accepted cardiac xenografts in CD4-/- mice. This rejection can be prevented by pretransplant DLI in the absence of any other treatment. Furthermore, we demonstrate that DLI activates alphabeta-TCR+CD3+CD4-CD8- double-negative (DN) regulatory T (Treg) cells in xenograft recipients, and that DLI-activated DN Treg cells can inhibit the proliferation of donor-specific xenoreactive CD4+ T cells in vitro. More importantly, adoptive transfer of DLI-activated DN Treg cells from xenograft recipients can suppress the proliferation of xenoreactive CD4+ T cells and their ability to produce IL-2 and IFN-gamma in vivo. Adoptive transfer of DLI-activated DN Treg cells also prevents CD4+ T cell-mediated cardiac xenograft rejection in an Ag-specific fashion. These data provide direct evidence that DLI can activate recipient DN Treg cells, which can induce donor-specific long-term cardiac xenograft survival by suppressing the proliferation and function of donor-specific CD4+ T cells in vivo.
authors.affiliation: Department of Laboratory Medicine and Pathobiology, Multi Organ Transplantation Program, Toronto General Research Institute, University Health Network, Ontario, Canada.
authors.forename: Wenhao
authors.initials: W
authors.lastname: Chen
authors.forename: Dejun
authors.initials: D
authors.lastname: Zhou
authors.forename: Jose R
authors.initials: JR
authors.lastname: Torrealba
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Waddell
authors.forename: David
authors.initials: D
authors.lastname: Grant
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology; D016207:Cytokines / Q000096:biosynthesis; D006084:Graft Rejection / Q000209:etiology; D006085:Graft Survival; D016027:Heart Transplantation / Q000276:immunology*; D008213:Lymphocyte Activation; D017710:Lymphocyte Transfusion; D051379:Mice; D008810:Mice, Inbred C57BL; D051381:Rats; D011917:Rats, Inbred Lew; D011920:Rats, Inbred WF; D015375:Receptors, Interleukin-2 / Q000032:analysis; D013601:T-Lymphocytes / Q000276:immunology*; D014019:Tissue Donors; D014183:Transplantation, Heterologous / Q000276:immunology*
chemical_list: D016207:Cytokines; D015375:Receptors, Interleukin-2