title: Expression of CTLA4-Ig by biolistically transfected mouse islets promotes islet allograft survival.
abstract: BACKGROUND
  Localized delivery of immunosuppressive molecules, limited to the graft site, may allow transplantation of tissue in the absence of systemic immunosuppressive agents. We tested whether purified mouse islets that had been engineered to produce human CTLA4-Ig locally at the graft site could survive in allogeneic recipients receiving no systemic immunosuppression.
  
  
  METHODS
  CBA (H2(k)) islets were subjected to biolistic (gene gun) transfection with a cDNA encoding human CTLA4-Ig under control of the human cytomegalovirus immediate early promoter. After 40-48 hr of culture, the transfected islets (500 per recipient) were transplanted beneath the renal capsule of alloxan-induced diabetic BALB/c (H2(d)) recipients.
  
  
  RESULTS
  Control grafts (n=10) consisting of islets biolistically transfected with the expression plasmid alone (i.e., no gene inserted) survived for 12.8+/-3.6 (mean +/- SD) days. In contrast, islets transfected with CTLA4-Ig (n=12) survived 66.8+/-61.5 days (P=0.01), with 50% demonstrating functional survival until follow-up was concluded at 50 (n=2), 130 (n=2), or 165 (n=2) days. Immunohistochemistry on grafts that survived long term showed well-granulated, insulin-positive islets lying adjacent to, but not infiltrated by, dense aggregates of mononuclear cells.
  
  
  CONCLUSIONS
  Transfection of allogeneic mouse islets with human CTLA4-Ig results in prolonged allograft survival. Although on histology mononuclear cells are present in the area of the transfected graft, they do not appear to infiltrate or destroy the islet graft.
authors.affiliation: Department of Surgery, University of Alberta, Edmonton, Canada.
authors.forename: A L
authors.initials: AL
authors.lastname: Gainer
authors.forename: G S
authors.initials: GS
authors.lastname: Korbutt
authors.forename: R V
authors.initials: RV
authors.lastname: Rajotte
authors.forename: G L
authors.initials: GL
authors.lastname: Warnock
authors.forename: J F
authors.initials: JF
authors.lastname: Elliott
mesh_terms: D000069594:Abatacept; D000818:Animals; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000235:genetics / Q000378:metabolism*; D019470:Biolistics; D060908:CTLA-4 Antigen; D006085:Graft Survival / Q000235:genetics / Q000276:immunology*; D006801:Humans; D018796:Immunoconjugates; D007328:Insulin / Q000378:metabolism; D007515:Islets of Langerhans / Q000276:immunology* / Q000378:metabolism; D016381:Islets of Langerhans Transplantation / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008808:Mice, Inbred CBA; D014184:Transplantation, Homologous
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; C556707:Ctla4 protein, mouse; D018796:Immunoconjugates; D007328:Insulin; D000069594:Abatacept