title: Lentivirally transduced recipient-derived dendritic cells serve to ex vivo expand functional FcRgamma-sufficient double-negative regulatory T cells.
abstract: alphabetaTCR(+)CD4(-)CD8(-) double-negative (DN) T regulatory (Treg) cells have recently been shown to suppress antigen-specific immune responses mediated by CD8(+) and CD4(+) T cells in mice and humans. In this study, we developed a system to expand DN Treg cells for transplantation therapy that exclusively uses recipient-derived immune cells and confers a high degree of safety as the protocol does not involve the direct injection of lentiviral vectors. Recipient-derived dendritic cells (DCs) were transduced with lentiviral vectors that express major histocompatibility complex class I L(d) antigen (LV-L(d)), which is expressed by the donor graft but is allogeneic to the graft recipient. LV-L(d)-transduced mature DCs (mDCs) were able to expand effectively both FcRgamma(-/-) and FcRgamma(+/+) DN T cells. After expansion with LV-L(d)-transduced mDCs, only the FcRgamma(+/+) DN Treg cells maintained their ability to suppress CD8(+) T cells in vitro. In addition, adoptive transfer of the FcRgamma(+/+) ex vivo expanded DN Treg cells significantly prolonged the survival of L(d+) skin grafts. This study is the first description of successful ex vivo expansion of antigen-specific DN Treg cells using genetically modified syngeneic DCs for adoptive immunotherapy and demonstrates that although FcRgamma(-/-) DN T cells can be expanded, they do not gain regulatory ability.
authors.affiliation: Department of Laboratory Medicine and Pathobiology, Multi Organ Transplantation Program, Toronto General Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Thomson
authors.forename: Miriam E
authors.initials: ME
authors.lastname: Mossoba
authors.forename: Christopher
authors.initials: C
authors.lastname: Siatskas
authors.forename: Wenhao
authors.initials: W
authors.lastname: Chen
authors.forename: April
authors.initials: A
authors.lastname: Sung
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Medin
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000818:Animals; D003713:Dendritic Cells / Q000276:immunology*; D005260:Female; D005822:Genetic Vectors; D006085:Graft Survival / Q000276:immunology; D006801:Humans; D016219:Immunotherapy, Adoptive / Q000379:methods; D066298:In Vitro Techniques; D016086:Lentivirus / Q000235:genetics*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D008822:Mice, Transgenic; D017452:Receptors, IgG / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D016038:Skin Transplantation / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D014161:Transduction, Genetic
chemical_list: D017452:Receptors, IgG