title: Differential expression of alpha-GAL epitopes (Galalpha1-3Galbeta1-4GlcNAc-R) on pig and mouse organs.
abstract: BACKGROUND
  Expression of the alpha-gal epitope in mice can be completely eliminated by disruption of the alpha1,3 galactosyltransferase gene. As an initial step for assessing the feasibility of this approach in the pig, it was of interest to compare the expression of alpha-gal epitopes in pig and mouse organs.
  
  
  METHODS
  Membranes from pig and mouse organ homogenates were analyzed for alpha-gal epitope expression by Western blots, enzyme-linked immunosorbent assay (ELISA), immunostaining of tissues, and ELISA inhibition assay.
  
  
  RESULTS
  Immunostaining of Western blots with human anti-Gal detected alpha-gal epitopes on glycoproteins from pig organs but not on glycoproteins from the corresponding mouse organs. ELISA with membrane homogenates and immunostaining of tissue sections demonstrated a much higher binding of human anti-Gal to alpha-gal epitopes on pig membranes than on mouse membranes. ELISA inhibition assay with monoclonal anti-Gal indicated that alpha-gal epitope expression in pig organs is up to 500-fold higher than in mouse organs.
  
  
  CONCLUSIONS
  Expression of alpha-gal epitopes in pig organs is many fold higher than in mouse organs. The abundance of these epitopes in pigs raises the question of whether pigs can properly develop without expression of alpha-gal epitopes.
authors.affiliation: Department of Microbiology and Immunology, MCP Hahnemann School of Medicine, Philadelphia, Pennsylvania 19129, USA.
authors.forename: M
authors.initials: M
authors.lastname: Tanemura
authors.forename: S
authors.initials: S
authors.lastname: Maruyama
authors.forename: U
authors.initials: U
authors.lastname: Galili
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000378:metabolism; D006801:Humans; D007158:Immunologic Techniques; D051379:Mice / Q000276:immunology / Q000378:metabolism*; D013194:Staining and Labeling; D013552:Swine / Q000276:immunology / Q000378:metabolism*; D014312:Trisaccharides / Q000276:immunology / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D014312:Trisaccharides; C076569:alpha-galactosyl epitope