title: Human leukocyte antigen I knockdown human embryonic stem cells induce host ignorance and achieve prolonged xenogeneic survival.
abstract: BACKGROUND
  Although human embryonic stem cells (hESC) have enormous potential for cell replacement therapy of heart failure, immune rejection of hESC derivatives inevitably would occur after transplantation. We therefore aimed to generate a hypoantigeneic hESC line with improved survival characteristics.
  
  
  RESULTS
  Using various in vivo, nonischemic, hindlimb xenotransplant models (immunocompetent and defined immunodefective mouse strains) as well as human in vitro T-cell and natural killer (NK)-cell assays, we revealed a central role for T cells in mediating hESC rejection. The NK-cell susceptibility of hESC in vivo was found to be low, and the NK response to hESC challenge in vitro was negligible. To reduce the antigenicity of hESC, we successfully generated human leukocyte antigen (HLA) I knockdown cells (hESC(siRNA+IB)) using both HLA I RNA interference (siRNA) and intrabody (IB) technology. HLA I expression was ≈99% reduced after 7 days and remained low for weeks. Cellular immune recognition of these hESC(siRNA+IB) was strongly reduced in both xenogeneic and allogeneic settings. Immune rejection was profoundly mitigated after hESC(siRNA+IB) transplantation into immunocompetent mice, and even long-term graft survival was achieved in one third of the animals without any immunosuppression. The survival benefit of hESC(siRNA+IB) was further confirmed under ischemic conditions in a left anterior descending coronary artery ligation model.
  
  
  CONCLUSIONS
  HLA I knockdown hESC(siRNA+IB) provoke T-cell ignorance and experience largely mitigated xenogeneic rejection. By generating hypoantigeneic hESC lines, the generation of acceptable hESC derivatives may become a practical concept and push cell replacement strategies forward.
authors.affiliation: Department of Cardiovascular Surgery, Stanford University, Stanford, CA, USA. t.deuse@uke.de
authors.forename: Tobias
authors.initials: T
authors.lastname: Deuse
authors.forename: Martina
authors.initials: M
authors.lastname: Seifert
authors.forename: Neil
authors.initials: N
authors.lastname: Phillips
authors.forename: Andrew
authors.initials: A
authors.lastname: Fire
authors.forename: Dolly
authors.initials: D
authors.lastname: Tyan
authors.forename: Mark
authors.initials: M
authors.lastname: Kay
authors.forename: Philip S
authors.initials: PS
authors.lastname: Tsao
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Hua
authors.forename: Joachim
authors.initials: J
authors.lastname: Velden
authors.forename: Thomas
authors.initials: T
authors.lastname: Eiermann
authors.forename: Hans-Dieter
authors.initials: HD
authors.lastname: Volk
authors.forename: Hermann
authors.initials: H
authors.lastname: Reichenspurner
authors.forename: Robert C
authors.initials: RC
authors.lastname: Robbins
authors.forename: Sonja
authors.initials: S
authors.lastname: Schrepfer
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000276:immunology; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000166:cytology / Q000276:immunology*; D055785:Gene Knockdown Techniques; D006085:Graft Survival / Q000276:immunology*; D006680:HLA Antigens / Q000235:genetics*; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology*; D007165:Immunosuppression Therapy; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D008819:Mice, Nude; D016513:Mice, SCID; D023421:Models, Animal; D033581:Stem Cell Transplantation; D013601:T-Lymphocytes / Q000276:immunology; D013997:Time Factors; D014183:Transplantation, Heterologous / Q000276:immunology*
chemical_list: D006680:HLA Antigens