title: Display of Fas ligand protein on cardiac vasculature as a novel means of regulating allograft rejection.
abstract: BACKGROUND
  Fas ligand (FasL) is a potent death-inducing molecule with important functions in immune homeostasis and tolerance to self-antigens. The complex biological activities of FasL and its inefficient expression using conventional gene transfer approaches limit its use for immunomodulation to prevent allograft rejection. We have recently generated a chimeric FasL with core streptavidin (SA-FasL) with potent apoptotic activity and designed a novel approach to display it on the surface of several cell types via biotinylation. We herein tested whether SA-FasL can also be displayed on vascular endothelial cells in the heart and examined its effect on graft survival after transplantation into syngeneic and allogeneic hosts.
  
  
  RESULTS
  SA-FasL was efficiently displayed on the vasculature of BALB/c hearts with a half-life of 9 days in vivo. Transplantation of hearts displaying SA-FasL into syngeneic hosts resulted in indefinite graft survival without detectable toxicity to the grafts and hosts. In contrast, transplantation of allogeneic C57BL/10 hearts displaying SA-FasL into BALB/c recipients resulted in graft rejection, but in a delayed fashion as compared with control hearts (mean survival time=17.4+/-5 versus 9.6+/-1 days). Allograft survival was further extended to 21+/-2.6 and 24+/-3 days (P<0.05) by intravenous treatment of graft recipients with 1 dose of SA-FasL-decorated donor splenocytes on days 2 and 6 after transplantation, respectively.
  
  
  CONCLUSIONS
  This study shows for the first time that exogenous proteins can be displayed on the endothelium of solid organs for therapeutic purposes. This approach provides a convenient and rapid means of displaying exogenous proteins on the surface of cells, tissues, and solid organs, with broad research and therapeutic implications.
authors.affiliation: Leah and Edward M. Frankel Laboratory of Bone Marrow Transplantation, Department of Pediatric Hematology Oncology, Schneider Children's Medical Center of Israel, Petach Tikva, Israel. anadir@012.net.il
authors.forename: Nadir
authors.initials: N
authors.lastname: Askenasy
authors.forename: Esma S
authors.initials: ES
authors.lastname: Yolcu
authors.forename: Zhiliang
authors.initials: Z
authors.lastname: Wang
authors.forename: Haval
authors.initials: H
authors.lastname: Shirwan
mesh_terms: D000818:Animals; D019921:Biotinylation; D002465:Cell Movement; D017690:Cell Transplantation; D003331:Coronary Vessels / Q000166:cytology; D004730:Endothelium, Vascular / Q000737:chemistry; D053222:Fas Ligand Protein; D006084:Graft Rejection / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D006085:Graft Survival; D016027:Heart Transplantation / Q000276:immunology / Q000473:pathology; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D009504:Neutrophils / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000032:analysis; D013154:Spleen / Q000166:cytology; D019809:Streptavidin / Q000235:genetics; D023001:Transplantation Tolerance; D014184:Transplantation, Homologous
chemical_list: D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D008562:Membrane Glycoproteins; D011993:Recombinant Fusion Proteins; D019809:Streptavidin