title: Phosphorylation of the synthetic hexasaccharide repeating unit is essential for the induction of antibodies to Clostridium difficile PSII cell wall polysaccharide.
abstract: Clostridium difficile is emerging worldwide as a major cause of nosocomial infections. The negatively charged PSII polysaccharide has been found in different strains of C. difficile and, thereby, represents an important target molecule for a possible carbohydrate-based vaccine. In order to identify a synthetic fragment that after conjugation to a protein carrier could be able to induce anti-PSII antibodies, we exploited a combination of chemical synthesis with immunochemistry, confocal immunofluorescence microscopy, and solid state NMR. We demonstrate that the phosphate group is crucial in synthetic glycans to mimic the native PSII polysaccharide; both native PSII and a phosphorylated synthetic hexasaccharide repeating unit conjugated to CRM(197) elicit comparable immunogenic responses in mice. This finding can aid design and selection of carbohydrate antigens to be explored as vaccine candidates.
authors.affiliation: Research Center, Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100 Siena, Italy. roberto.adamo@novartis.com
authors.forename: Roberto
authors.initials: R
authors.lastname: Adamo
authors.forename: Maria R
authors.initials: MR
authors.lastname: Romano
authors.forename: Francesco
authors.initials: F
authors.lastname: Berti
authors.forename: Rosanna
authors.initials: R
authors.lastname: Leuzzi
authors.forename: Marta
authors.initials: M
authors.lastname: Tontini
authors.forename: Elisa
authors.initials: E
authors.lastname: Danieli
authors.forename: Emilia
authors.initials: E
authors.lastname: Cappelletti
authors.forename: Osman S
authors.initials: OS
authors.lastname: Cakici
authors.forename: Erwin
authors.initials: E
authors.lastname: Swennen
authors.forename: Vittoria
authors.initials: V
authors.lastname: Pinto
authors.forename: Barbara
authors.initials: B
authors.lastname: Brogioni
authors.forename: Daniela
authors.initials: D
authors.lastname: Proietti
authors.forename: Cesira L
authors.initials: CL
authors.lastname: Galeotti
authors.forename: Luigi
authors.initials: L
authors.lastname: Lay
authors.forename: Mario A
authors.initials: MA
authors.lastname: Monteiro
authors.forename: Maria
authors.initials: M
authors.lastname: Scarselli
authors.forename: Paolo
authors.initials: P
authors.lastname: Costantino
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology; D000906:Antibodies / Q000737:chemistry; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry; D002473:Cell Wall / Q000276:immunology; D016360:Clostridioides difficile / Q000276:immunology* / Q000378:metabolism*; D003428:Cross Infection / Q000188:drug therapy; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D051379:Mice; D018613:Microscopy, Confocal / Q000379:methods; D008956:Models, Chemical; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry; D010766:Phosphorylation; D011134:Polysaccharides / Q000737:chemistry*; D014612:Vaccines / Q000737:chemistry
chemical_list: D000890:Anti-Infective Agents; D000906:Antibodies; D002241:Carbohydrates; D009844:Oligosaccharides; D011134:Polysaccharides; D014612:Vaccines