Mucosal surfaces are colonized by highly diverse commensal microbiota. Coating with secretory IgA (SIgA) promotes the survival of commensal bacteria while it inhibits the invasion by pathogens. Bacterial coating could be mediated by antigen-specific SIgA recognition, polyreactivity, and/or by the SIgA-associated glycans. In contrast to many in vitro studies, only a few reported the effect of SIgA glycans in vivo. Here, we used a germ-free antibody-free newborn piglets model to compare the protective effect of SIgA, SIgA with enzymatically removed N-glycans, Fab, and Fc containing the secretory component (Fc-SC) during oral necrotoxigenic E. coli O55 challenge. SIgA, Fab, and Fc-SC were protective, whereas removal of N-glycans from SIgA reduced SIgA-mediated protection as demonstrated by piglets' intestinal histology, clinical status, and survival. In vitro analyses indicated that deglycosylation of SIgA did not reduce agglutination of E. coli O55. These findings highlight the role of SIgA-associated N-glycans in protection. Further structural studies of SIgA-associated glycans would lead to the identification of those involved in the species-specific inhibition of attachment to corresponding epithelial cells.

• MeSH
• Agglutination MeSH
• Escherichia coli physiology   MeSH
• Glycosylation MeSH
• Germ-Free Life MeSH
• Immunoglobulin A, Secretory metabolism   MeSH
• Immunoglobulin Fab Fragments metabolism   MeSH
• Escherichia coli Infections immunology   MeSH
• Single-Chain Antibodies metabolism   MeSH
• Animals, Newborn MeSH
• Disease Resistance MeSH
• Polysaccharides metabolism   MeSH
• Swine MeSH
• Pregnancy MeSH
• Animals MeSH
• Check Tag
• Pregnancy MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Immunoglobulin A, Secretory MeSH
• Immunoglobulin Fab Fragments MeSH
• Single-Chain Antibodies MeSH
• Polysaccharides MeSH