title: Expression of NeuGc on Pig Corneas and Its Potential Significance in Pig Corneal Xenotransplantation.
abstract: OBJECTIVE
  Pigs expressing neither galactose-α1,3-galactose (Gal) nor N-glycolylneuraminic acid (NeuGc) take xenotransplantation one step closer to the clinic. Our aims were (1) to document the lack of NeuGc expression on corneas and aortas and cultured endothelial cells [aortic endothelial cells (AECs); corneal (CECs)] of GTKO/NeuGcKO pigs, and (2) to investigate whether the absence of NeuGc reduced human antibody binding to the tissues and cells.
  
  
  METHODS
  Wild-type (WT), GTKO, and GTKO/NeuGcKO pigs were used for the study. Human tissues and cultured cells were negative controls. Immunofluorescence staining was performed using anti-Gal and anti-NeuGc antibodies, and human IgM and IgG binding to tissues was determined. Flow cytometric analysis was used to determine Gal and NeuGc expression on cultured CECs and AECs and to measure human IgM/IgG binding to these cells.
  
  
  RESULTS
  Both Gal and NeuGc were detected on WT pig corneas and aortas. Although GTKO pigs expressed NeuGc, neither humans nor GTKO/NeuGcKO pigs expressed Gal or NeuGc. Human IgM/IgG binding to corneas and aortas from GTKO and GTKO/NeuGcKO pigs was reduced compared with binding to WT pigs. Human antibody binding to GTKO/NeuGcKO AECs was significantly less than that to GTKO AECs, but there was no significant difference in binding between GTKO and GTKO/NeuGcKO CECs.
  
  
  CONCLUSIONS
  The absence of NeuGc on GTKO aortic tissue and AECs is associated with reduced human antibody binding, and possibly will provide a better outcome in clinical xenotransplantation using vascularized organs. For clinical corneal xenotransplantation, the absence of NeuGc expression on GTKO/NeuGcKO pig corneas may not prove an advantage over GTKO corneas.
authors.affiliation: *Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA; †Department of Surgery, Indiana University School of Medicine, Indianapolis, IN; ‡National Swine Resource and Research Center, Columbia, MO; and §Revivicor, Blacksburg, VA.
authors.forename: Whayoung
authors.initials: W
authors.lastname: Lee
authors.forename: Yuko
authors.initials: Y
authors.lastname: Miyagawa
authors.forename: Cassandra
authors.initials: C
authors.lastname: Long
authors.forename: Burcin
authors.initials: B
authors.lastname: Ekser
authors.forename: Eric
authors.initials: E
authors.lastname: Walters
authors.forename: Jagdeece
authors.initials: J
authors.lastname: Ramsoondar
authors.forename: David
authors.initials: D
authors.lastname: Ayares
authors.forename: A Joseph
authors.initials: AJ
authors.lastname: Tector
authors.forename: David K C
authors.initials: DK
authors.lastname: Cooper
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Hara
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003315:Cornea / Q000378:metabolism* / Q000473:pathology; D003316:Corneal Diseases / Q000601:surgery*; D016039:Corneal Transplantation; D005434:Flow Cytometry; D006801:Humans; D009438:Neuraminic Acids / Q000378:metabolism*; D013552:Swine; D014183:Transplantation, Heterologous
chemical_list: D009438:Neuraminic Acids; C032592:N-glycolylneuraminic acid