title: Protection against hyperacute xenograft rejection of transgenic rat hearts expressing human decay accelerating factor (DAF) transplanted into primates.
abstract: BACKGROUND
  Production of transgenic pigs for multiple transgenes is part of a potential strategy to prevent immunological events involved in xenograft rejection. Use of a genetically engineerable rodent as a donor in primates could allow testing in vivo of the effects of different transgenes on controlling xenograft rejection. As a first step in the development of a donor containing multiple transgenes, transgenic rats for human decay-accelerating factor (DAF) were used as heart donors to test their resistance against complement (C)-mediated rejection by non-human primates.
  
  
  METHODS
  Transgenic rats were generated by using a construct containing the human DAF cDNA under the transcriptional control of the endothelial cell (EC)-specific human ICAM-2 promoter. DAF expression was evaluated by immunohistology and by FACS analysis of purified ECs. Resistance of transgenic hearts against C-mediated damage was evaluated by ex vivo perfusion with human serum and by transplantation into cynomolgus monkeys.
  
  
  RESULTS
  Immunohistological analysis of DAF expression in several organs from two transgenic lines showed uniform expression on the endothelium of all blood vessels. ECs purified from transgenic hearts showed 50% DAF expression compared to human ECs and >70% reduction of C-dependent cell lysis compared to control rat ECs. Hemizygous transgenic hearts perfused with human serum showed normal function for >60 min vs. 11. 2 +/- 1.7 min in controls. Hemi- or homozygous transgenic hearts transplanted into cynomolgus monkeys showed longer survival (15.2 +/- 7 min and >4.5 hr, respectively) than controls (5.5 +/- 1.4 min). In contrast to hyperacutely rejected control hearts, rejected homozygous DAF hearts showed signs of acute vascular rejection (AVR) characterized by edema, hemorrhage, and an intense PMN infiltration.
  
  
  CONCLUSIONS
  We demonstrate that endothelial-specific DAF expression increased heart transplant survival in a rat-to-primate model of xenotransplantation. This will aid in the analysis of AVR and of new genes that may inhibit this form of rejection, thus helping to define strategies for the production of transgenic pigs.
authors.affiliation: INSERM U437 "Immunointervention en Allo et Xénotransplantation" and Institut de Transplantation et de Recherche en Transplantation, Nantes, France.
authors.forename: B
authors.initials: B
authors.lastname: Charreau
authors.forename: S
authors.initials: S
authors.lastname: Ménoret
authors.forename: L
authors.initials: L
authors.lastname: Tesson
authors.forename: A
authors.initials: A
authors.lastname: Azimzadeh
authors.forename: M
authors.initials: M
authors.lastname: Audet
authors.forename: P
authors.initials: P
authors.lastname: Wolf
authors.forename: R
authors.initials: R
authors.lastname: Marquet
authors.forename: C
authors.initials: C
authors.lastname: Verbakel
authors.forename: J
authors.initials: J
authors.lastname: Ijzermans
authors.forename: P
authors.initials: P
authors.lastname: Cowan
authors.forename: M
authors.initials: M
authors.lastname: Pearse
authors.forename: A
authors.initials: A
authors.lastname: d'Apice
authors.forename: J P
authors.initials: JP
authors.lastname: Soulillou
authors.forename: I
authors.initials: I
authors.lastname: Anegon
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D000906:Antibodies / Q000378:metabolism; D018958:CD55 Antigens / Q000235:genetics*; D004727:Endothelium / Q000378:metabolism; D005260:Female; D006084:Graft Rejection / Q000473:pathology / Q000517:prevention & control*; D016027:Heart Transplantation; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008252:Macaca fascicularis; D008297:Male; D009206:Myocardium / Q000473:pathology; D009336:Necrosis; D009504:Neutrophils / Q000473:pathology; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains; D017207:Rats, Sprague-Dawley; D019076:Transgenes; D014183:Transplantation, Heterologous
chemical_list: D000906:Antibodies; D018958:CD55 Antigens