Enterotoxigenic Escherichia coli (ETEC) represents a major cause of morbidity and mortality in the human population. In particular, ETEC infections affect children under the age of five from low-middle income countries. However, there is no licensed vaccine against this pathogen. ETEC vaccine development is challenging since this pathotype expresses a wide variety of antigenically diverse virulence factors whose genes can be modified due to ETEC genetic plasticity. To overcome this challenge, we propose the use of outer membrane vesicles (OMVs) isolated from two ETEC clinical strains. In these OMVs, proteomic studies revealed the presence of important immunogens, such as heat-labile toxin, colonization factors, adhesins and mucinases. Furthermore, these vesicles proved to be immunogenic after subcutaneous administration in BALB/c mice. Since ETEC is an enteropathogen, it is necessary to induce both systemic and mucosal immunity. For this purpose, the vesicles, free or encapsulated in zein nanoparticles coated with a Gantrez®-mannosamine conjugate, were administered orally. Biodistribution studies showed that the encapsulation of OMVs delayed the transit through the gut. These results were confirmed by in vivo study, in which OMV encapsulation resulted in higher levels of specific antibodies IgG2a. Further studies are needed to evaluate the protection efficacy of this vaccine approach.

• Klíčová slova
• Enterotoxigenic Escherichia coli (ETEC), Gantrez, mannosamine, nanoparticles, oral vaccine, outer membrane vesicle (OMV),
• Publikační typ
• časopisecké články MeSH

The ability to adhere via colonization factors to specific receptors located on the intestinal mucosa is a key virulence factor in enterotoxigenic Escherichia coli (ETEC) pathogenesis. Here, the potential glycosphingolipid receptors of the novel human ETEC colonization factor CS30 were examined by binding of CS30-expressing bacteria to glycosphingolipids on thin-layer chromatograms. We thereby found a highly specific binding of CS30-expressing bacteria to a fast-migrating acid glycosphingolipid of human and porcine small intestine, while no binding was obtained with a mutant ETEC strain unable to express CS30 fimbriae. The CS30 binding glycosphingolipid from human small intestine was isolated and characterized by mass spectrometry as sulfatide (SO3-3Galβ1Cer). Comparative binding studies using sulfatides with different ceramide compositions gave a preferential binding of CS30 to sulfatide with d18:1-h24:0 ceramide. This ceramide species of sulfatide was also isolated from human small intestine and characterized by mass spectrometry and antibody binding. These studies implicate sulfatide as candidate receptor for mediating attachment of CS30-fimbriated ETEC to human and porcine small intestinal cells. Our findings may be a basis for designing receptor saccharide analogues for inhibition of the intestinal adhesion of CS30-expressing E. coli.

• Klíčová slova
• Enterotoxigenic E. coli, carbohydrate binding, colonization factor CS30, glycosphingolipid characterization, microbial adhesion, sulfatide,
• MeSH
• bakteriální adheze * MeSH
• ceramidy analýza   MeSH
• enterotoxigenní Escherichia coli metabolismus   MeSH
• faktory virulence metabolismus   MeSH
• glykosfingolipidy metabolismus   MeSH
• lidé MeSH
• prasata MeSH
• proteiny fimbrií genetika   metabolismus   MeSH
• proteiny z Escherichia coli metabolismus   MeSH
• střevní sliznice cytologie   mikrobiologie   MeSH
• sulfoglykosfingolipidy metabolismus   MeSH
• tenké střevo cytologie   mikrobiologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ceramidy MeSH
• colonization factor antigens MeSH Prohlížeč
• faktory virulence MeSH
• glykosfingolipidy MeSH
• proteiny fimbrií MeSH
• proteiny z Escherichia coli MeSH
• sulfoglykosfingolipidy MeSH