title: Normal human serum contains high levels of anti-Gal alpha 1-4GlcNAc antibodies.
abstract: BACKGROUND
  Natural xenoreactive antibodies (Abs) directed against the Bdi-epitope (Gal alpha 1-3Gal beta) on the cells of non-primate mammals take part in hyperacute rejection of xenotransplanted organs. We found that some Abs, which were one-step affinity purified on Bdi-Sepharose, cross-reacted with the disaccharide Gal alpha 1-4GlcNAc beta. The epitope Gal alpha 1-4GlcNAc has not been identified on mammals or bacterial polysaccharides yet.
  
  
  METHODS
  To isolate the antibodies of the corresponding specificity the disaccharide was immobilized on Sepharose and antibodies were affinity purified from pooled serum of blood group O individuals.
  
  
  RESULTS
  These one-step purified Abs cross-reacted with Bdi, but after a prior absorption step on Bdi-Sepharose no cross-reactivity with Bdi was observed any longer. Surprisingly, the quantity of anti-Gal alpha 1-4GlcNAc isolated from the same serum pool, 4-7 microg/ml, was equal to that of anti-Bdi or more. Independently of ABO blood groups all the tested healthy donors had anti-Gal alpha 1-4GlcNAc Abs at a similar level. Monospecific anti-Gal alpha 1-4GlcNAc Abs were not cytotoxic towards porcine cells.
  
  
  CONCLUSIONS
  1. The actual concentration of monospecific, xenoreactive Gal alpha 1-3Gal beta Abs in blood may be considerably lower than the value referred to in the literature for 'anti-alpha Gal' or 'anti-Galili' antibodies. 2. Anti-Gal alpha 1-4GlcNAc Abs seem not to be important for xenotransplantation.
authors.affiliation: Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russian Federation.
authors.forename: Polina
authors.initials: P
authors.lastname: Obukhova
authors.forename: Robert
authors.initials: R
authors.lastname: Rieben
authors.forename: Nicolai
authors.initials: N
authors.lastname: Bovin
mesh_terms: D000906:Antibodies / Q000097:blood* / Q000302:isolation & purification; D000918:Antibody Specificity; D000936:Antigen-Antibody Complex / Q000032:analysis; D004187:Disaccharides / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005690:Galactose / Q000276:immunology; D006801:Humans; D007700:Kinetics; D012016:Reference Values; D012703:Serotyping; D014312:Trisaccharides / Q000276:immunology
chemical_list: D000906:Antibodies; D000936:Antigen-Antibody Complex; D004187:Disaccharides; D014312:Trisaccharides; D005690:Galactose