title: The immune response to group B streptococcus type III capsular polysaccharide is directed to the -Glc-GlcNAc-Gal- backbone epitope.
abstract: The structures of the branched capsular polysaccharides of group B streptococcus type III (GBSIIIPS) and Streptococcus pneumoniae type 14 (Pn14PS) are identical apart from the (α2→3)-linked sialic acid in the side chains of GBSIIIPS. The present study tries to determine the minimal epitope in GBSIIIPS, using both a panel of anti-Pn14PS mouse sera and sera of humans vaccinated with either Pn14PS or GBSIIIPS. Type-specific Pn14PS antibodies that recognize the branched structure of Pn14PS have a low affinity for the native GBSIIIPS. Desialylation of GBSIIIPS results in dramatically higher affinity of anti-Pn14PS antibodies. Epitope specific anti-Pn14PS mouse antibodies and human sera of PCV7 vaccinees only recognized structures with the branching element -Glc-(Gal-)GlcNAc-, in particular -Gal-Glc-(Gal-)GlcNAc- in Pn14PS. On the other hand anti-GBSIIIPS human antibodies recognize predominantly the linear structure in the backbone of Pn14PS or GBSIIIPS, i.e., -Glc-GlcNAc-Gal-. This difference in antigenicity of Pn14PS and GBSIIIPS is in agreement with the difference in flexibility of the two polysaccharides caused by the presence or absence of sialic acid.
authors: Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands. safari@eijkman.go.id
authors: Dodi
authors: D
authors: Safari
authors: Huberta A T
authors: HA
authors: Dekker
authors: Ger T
authors: GT
authors: Rijkers
authors: Arie
authors: A
authors: van der Ende
authors: Johannis P
authors: JP
authors: Kamerling
authors: Harm
authors: H
authors: Snippe
mesh_terms: D000117:Acetylglucosamine / Q000276:immunology*; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D016667:Bacterial Capsules / Q000737:chemistry / Q000276:immunology*; D002240:Carbohydrate Sequence; D002417:Cattle; D000939:Epitopes / Q000737:chemistry* / Q000276:immunology*; D005690:Galactose / Q000276:immunology*; D005947:Glucose / Q000276:immunology*; D006001:Glycoconjugates / Q000378:metabolism; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D019158:N-Acetylneuraminic Acid / Q000276:immunology; D009844:Oligosaccharides / Q000737:chemistry / Q000276:immunology; D011485:Protein Binding; D044967:Serum; D012710:Serum Albumin, Bovine / Q000378:metabolism; D013292:Streptococcus agalactiae / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000939:Epitopes; D006001:Glycoconjugates; D009844:Oligosaccharides; D012710:Serum Albumin, Bovine; D019158:N-Acetylneuraminic Acid; D005947:Glucose; D000117:Acetylglucosamine; D005690:Galactose