The role of oligosaccharides in virus-host interactions : Application to Norovirus contamination of oysters

• Main Author: Auger, Audrey
• Other Authors: Unité de Glycobiologie Structurale et Fonctionnelle - UMR 8576 (UGSF), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université de Lille, Frédéric Chirat
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2023
• Subjects: Hbga; Glycomic; Host-Pathogen interaction; Norovirus; Oyster; Antigènes de groupes sanguins tissulaires; [SDV.BC]Life Sciences [q-bio]/Cellular Biology; Crassostrea gigas
• Online Access: https://theses.hal.science/tel-04529096; https://theses.hal.science/tel-04529096/document; https://theses.hal.science/tel-04529096/file/These_AUGER_Audrey.pdf

Noroviruses (NoVs) are the most common cause of gastroenteritis worldwide. Contamination occurs mainly from person to person or through the consumption of contaminated foods such as fruits, vegetables or shellfish. In the latter case, oysters are known to be excellent vectors, particularly due to their raw consumption, proximity to human sewage, filtration capacity and specific retention of NoVs. Using various lectins, antibodies and virus-like particles (VLPs), it has been demonstrated that specific retention of NoVs relies on the presence of A antigen (A Ag) in oysters.To highlight the presence and distribution of Histo-blood group antigens on glycoconjugates from the oyster species Crassostrea gigas and Ostrea edulis, we established N and O-glycomes from mantle, gills and digestive tissue. N-glycans were sequentially released by peptide:N-glycosidase F (PNGase F) and A. After permethylation, structural analyses by MALDI-QIT-TOF revealed the presence of A and A Lewis b (ALeb) Ags for both species, as well as H and HLeb Ags for O. edulis only. Deutero-permethylation instead of permethylation, followed by MALDI-MSn analyses revealed the presence of naturally methylated N glycans, as demonstrated in the oyster Crassostrea virginica. To identify the monosaccharides carrying methyl groups and specify their position, the N-glycans monosaccharides were converted into their itol acetate derivative and analyzed by gas chromatography coupled with EI-MS mass spectrometry. This revealed the presence of a methyl group on carbon 3 of N acetylgalactosamine residues in A Ags for both species. Fucose residues also appeared methylated on their carbon 3 or 4 for C. gigas and O. edulis oysters, respectively. These methyl-fucose residues were identified in Leb Ag for both species, and in A Ag only for O. edulis. To extend these analyses to O-glycans, a mucin preparation protocol was implemented and O-glycans were released by reductive β-elimination, permethylated or perdeuteromethylated and analysed by MSn mass spectrometry. Our ...