title: Explaining the Serological Characteristics of Streptococcus suis Serotypes 1 and 1/2 from Their Capsular Polysaccharide Structure and Biosynthesis.
abstract: The capsular polysaccharide (CPS) is a major virulence factor in many encapsulated pathogens, as it is the case for Streptococcus suis, an important swine pathogen and emerging zoonotic agent. Moreover, the CPS is the antigen at the origin of S. suis classification into serotypes. Hence, analyses of the CPS structure are an essential step to dissect its role in virulence and the serological relations between important serotypes. Here, the CPSs of serotypes 1 and 1/2 were purified and characterized for the first time. Chemical and spectroscopic data gave the following repeating unit sequences: [6)[Neu5Ac(α2-6)GalNAc(β1-4)GlcNAc(β1-3)]Gal(β1-3)Gal(β1-4)Glc(β1-]n (serotype 1) and [4)[Neu5Ac(α2-6)GalNAc(β1-4)GlcNAc(β1-3)]Gal(β1-4)[Gal(α1-3)]Rha(β1-4)Glc(β1-]n (serotype 1/2). The Sambucus nigra lectin, which recognizes the Neu5Ac(α2-6)Gal/GalNAc sequence, showed binding to both CPSs. Compared with previously characterized serotype 14 and 2 CPSs, N-acetylgalactosamine replaces galactose as the sugar bearing the sialic acid residue in the side chain. Serological analyses of the cross-reaction of serotype 1/2 with serotypes 1 and 2 and that between serotypes 1 and 14 suggested that the side chain, and more particularly the terminal sialic acid, constitutes one important epitope for serotypes 1/2 and 2. The side chain is also an important serological determinant for serotype 1, yet sialic acid seems to play a limited role. In contrast, the side chain does not seem to be part of a major epitope for serotype 14. These results contribute to the understanding of the relationship between S. suis serotypes and provide the basis for improving diagnostic tools.
authors.affiliation: From the Food Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Hyacinthe, Quebec J2S 8E3, Canada, the Swine and Poultry Infectious Disease Research Centre and.
authors.forename: Marie-Rose
authors.initials: MR
authors.lastname: Van Calsteren
authors.affiliation: the Swine and Poultry Infectious Disease Research Centre and Research Group on Infectious Diseases of Swine, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec J2S 2M2, Canada.
authors.forename: Guillaume
authors.identifier: http://orcid.org/0000-0001-7158-9594
authors.initials: G
authors.lastname: Goyette-Desjardins
authors.affiliation: From the Food Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Hyacinthe, Quebec J2S 8E3, Canada.
authors.forename: Fleur
authors.initials: F
authors.lastname: Gagnon
authors.affiliation: the Bacterial and Parasitic Diseases Research Division, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305 0856, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Okura
authors.affiliation: the Bacterial and Parasitic Diseases Research Division, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305 0856, Japan, the United Graduate School of Veterinary Sciences, Gifu University, Gifu, Gifu 501 1193, Japan, and.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Takamatsu
authors.affiliation: the Department of Chemistry, Université du Québec à Montréal, Montreal, Quebec H3C 3P8, Canada.
authors.forename: René
authors.initials: R
authors.lastname: Roy
authors.affiliation: the Swine and Poultry Infectious Disease Research Centre and Research Group on Infectious Diseases of Swine, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec J2S 2M2, Canada.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Gottschalk
authors.affiliation: the Swine and Poultry Infectious Disease Research Centre and Research Group on Infectious Diseases of Swine, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, Quebec J2S 2M2, Canada, mariela.segura@umontreal.ca.
authors.forename: Mariela
authors.initials: M
authors.lastname: Segura
mesh_terms: D016667:Bacterial Capsules / Q000276:immunology* / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000276:immunology* / Q000378:metabolism; D065288:Serogroup; D017011:Streptococcus suis / Q000276:immunology* / Q000378:metabolism
chemical_list: D011135:Polysaccharides, Bacterial
keywords: Streptococcus; carbohydrate structure; chemical biology; immunochemistry; polysaccharide; sialic acid