Composition and antigenic activity of the oligosaccharide moiety of Haemophilus influenzae type b lipooligosaccharide.
The oligosaccharide moiety of the lipooligosaccharide of Haemophilus influenzae type b strain Eag was isolated from the lipid component by mild acid hydrolysis and purified by gel filtration. Fast atom bombardment-mass spectrometry indicated that the lipid-free oligosaccharide had a basic molecular weight of 1,768; polysaccharides comparable to high-molecular-weight O side chains were not found. Glucose, galactose, galactosamine, heptose, 3-deoxy-D-manno-2-octulosonic acid (KDO), ethanolamine, and phosphate were identified in the lipid-free oligosaccharide by colorimetric assays, gas chromatography-mass spectrometry, or an amino acid analyzer. The presence of KDO was not clearly established by a thiobarbituric acid assay or by growth inhibition by a diazaborine derivative thought to block KDO synthesis. However, the semicarbizide assay and gas chromatography-mass spectrometry confirmed the presence of KDO. Lectin precipitation by Eag lipooligosaccharide in gels indicated that beta-D-galactose was present and that some of this monosaccharide was a terminal, nonreducing residue linked to N-acetyl-D-galactosamine. The lipid-free oligosaccharide was antigenic and completely inhibited lipooligosaccharide antibody (predominantly immunoglobulin G [IgG] and IgM) in an enzyme-linked immunosorbent assay, whereas the solubilized lipid A moiety did not. H. influenzae type b lipid-free oligosaccharide differed from core oligosaccharide of Salmonella lipooligosaccharide by the presence of galactosamine and a smaller percentage of heptose and KDO.
D004983:Ethanolamines / Q000032:analysis; D005688:Galactosamine / Q000032:analysis; D005690:Galactose / Q000032:analysis; D005947:Glucose / Q000032:analysis; D006193:Haemophilus influenzae / Q000032:analysis / Q000276:immunology*; D006539:Heptoses / Q000032:analysis; D008070:Lipopolysaccharides / Q000032:analysis / Q000276:immunology*; D008970:Molecular Weight; D009844:Oligosaccharides / Q000032:analysis / Q000276:immunology*; D010710:Phosphates / Q000032:analysis; D013400:Sugar Acids / Q000032:analysis
D004983:Ethanolamines; D006539:Heptoses; D008070:Lipopolysaccharides; D009844:Oligosaccharides; D010710:Phosphates; D013400:Sugar Acids; C002532:2-keto-3-deoxyoctonate; D005688:Galactosamine; D005947:Glucose; D005690:Galactose