title: Endothelial cells derived from pigs lacking Gal alpha(1,3)Gal: no reduction of human leukocyte adhesion and natural killer cell cytotoxicity.
abstract: BACKGROUND
  The expression of galactose-alpha(1,3)galactose (Gal) on porcine cells represents a major barrier to xenotransplantation. The generation of Gal-/- pigs to overcome this barrier redirected the focus of research to other rejection mechanisms, including cellular immunity. The present in vitro study investigated (1) the adhesive interactions between human leukocyte subsets and primary endothelial cells derived from inbred Gal-/- and Gal+/+ pigs, and (2) the susceptibility of such Gal-/- porcine endothelial cells to human natural killer (NK) cell cytotoxicity.
  
  
  METHODS
  Primary porcine aortic endothelial cells (PAEC) were isolated from Gal-/- (PAEC-Gal-/-) and Gal (PAEC-Gal+/+) pigs. Human peripheral blood mononuclear cells (PBMC), polymorphonuclear neutrophils (PMN), and NK cells were isolated from healthy volunteers and tested in functional adhesion and cytotoxicity assays.
  
  
  RESULTS
  Adhesion of human PBMC, PMN, or purified NK cells on PAEC-Gal-/- cells was not different from that on PAEC-Gal+/+ cells. Comparing the different leukocyte subsets of PBMC, a preferential adhesion of NK and B cells on both PAEC-Gal-/- and PAEC-Gal+/+ was detected. Tumor-necrosis factor-alpha stimulation of PAEC-Gal-/- and PAEC-Gal+/+ induced an increase of CD62E and CD106 expression and increased cellular adhesion, in particular, of PMN. The lack of Gal-/- expression on PAEC-Gal cells did not prevent xenogeneic human NK-cell cytotoxicity mediated by freshly isolated or interleukin-2-activated NK cells.
  
  
  CONCLUSIONS
  Neither human leukocyte adhesion nor xenogeneic NK-cell cytotoxicity against PAEC are impaired by the lack of Gal, indicating that Gal is not a dominant target of cellular rejection.
authors.affiliation: Laboratory for Transplantation Immunology, Department of Internal Medicine, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Bettina C
authors.initials: BC
authors.lastname: Baumann
authors.forename: Mårten K J
authors.initials: MK
authors.lastname: Schneider
authors.forename: Benjamin G
authors.initials: BG
authors.lastname: Lilienfeld
authors.forename: Maria A
authors.initials: MA
authors.lastname: Antsiferova
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Rhyner
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Hawley
authors.forename: Jörg D
authors.initials: JD
authors.lastname: Seebach
mesh_terms: D000818:Animals; D001011:Aorta; D002448:Cell Adhesion / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D004187:Disaccharides / Q000172:deficiency*; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology*; D005434:Flow Cytometry; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D007962:Leukocytes / Q000276:immunology*; D013552:Swine / Q000235:genetics
chemical_list: D004187:Disaccharides; C055075:galactosyl-(1-3)galactose