title: Intravenous immunoglobulin contains a broad repertoire of anticarbohydrate antibodies that is not restricted to the IgG2 subclass.
abstract: BACKGROUND
  Specificities for carbohydrate IgG antibodies, thought to be predominantly of the IgG2 subclass, have never been broadly examined in healthy human subjects.
  
  
  OBJECTIVE
  To examine commercial intravenous immunoglobulin (IVIG) preparations for their ability to recognize a wide range of glycans and to determine the contribution of IgG2 to the binding pattern observed.
  
  
  METHODS
  We used a glycan microarray to evaluate IVIG preparations and a control mix of similar proportions of human myeloma IgG1 and IgG2 for binding to 377 glycans, courtesy of the Consortium for Functional Glycomics Core H. Glycans recognized were categorized using public databases for their likely cellular sources. IgG2 was depleted from IVIG by using immunoaffinity chromatography, and depletion was confirmed by using nephelometry and surface plasmon resonance.
  
  
  RESULTS
  Nearly half of the glycans bound IgG. Some of the glycans with the greatest antibody binding can be found in structures of human pathogenic bacteria (eg, Streptococcus pneumoniae, Mycobacterium tuberculosis, Vibrio cholera) and nonpathogenic bacteria, including LPS and lipoteichoic acid, capsular polysaccharides, and exopolysaccharides. Surprisingly, depletion of IgG2 had only a modest effect on anticarbohydrate recognition patterns compared with the starting IVIG preparation. Little to no binding activity was detected to human endogenous glycans, including tumor-associated antigens.
  
  
  CONCLUSIONS
  This novel, comprehensive analysis provides evidence that IVIG contains a much wider range than previously appreciated of anticarbohydrate IgG antibodies, including those recognizing both pathogenic and non-pathogen-associated prokaryotic glycans.
authors.affiliation: Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, MD 21224-6821, USA.
authors.forename: Stephan
authors.initials: S
authors.lastname: von Gunten
authors.forename: David F
authors.initials: DF
authors.lastname: Smith
authors.forename: Richard D
authors.initials: RD
authors.lastname: Cummings
authors.forename: Stefan
authors.initials: S
authors.lastname: Riedel
authors.forename: Sylvia
authors.initials: S
authors.lastname: Miescher
authors.forename: Alexander
authors.initials: A
authors.lastname: Schaub
authors.forename: Robert G
authors.initials: RG
authors.lastname: Hamilton
authors.forename: Bruce S
authors.initials: BS
authors.lastname: Bochner
mesh_terms: D000906:Antibodies / Q000276:immunology*; D001419:Bacteria / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D016756:Immunoglobulins, Intravenous / Q000276:immunology*; D046228:Microarray Analysis; D011134:Polysaccharides / Q000276:immunology*
chemical_list: D000906:Antibodies; D007074:Immunoglobulin G; D016756:Immunoglobulins, Intravenous; D011134:Polysaccharides