title: Oral infection with enteropathogenic Escherichia coli triggers immune response and intestinal histological alterations in mice selected for their minimal acute inflammatory responses.
abstract: Enteropathogenic Escherichia coli (EPEC), a leading cause of infant diarrhea, is an important public health problem in Brazil and other developing countries. In vitro assays of bacterial adhesion to cultured cells are important tools for studying bacterial pathogenicity but do not reproduce all the events that occur in natural infections. In this study, the effects of oral infection with EPEC on mice selected for their minimal acute inflammatory response (AIR min) were evaluated. Mice were orally infected with EPEC and variations in body weight, bacterial shedding and antibody production observed. The infected animals developed seric and secretory anti-EPEC antibodies; however, neither mortality nor diarrhea was observed. Light microscopy of their intestines demonstrated histological modifications that were not present in controls. However, electron microscopy did not show bacteria attached to the intestinal epithelia to form attaching and effacing lesions, characteristic of EPEC in humans. The bacteria were detected in Peyer's patches and intestinal contents up to 5 hr post-infection. When human anti-EPEC secretory immunoglobulin A or avian immunoglobulin Y antibodies were administered to infected animals, they developed minor histological alterations compared with non-treated animals. In summary, it was found that EPEC triggers immune responses and intestinal histological alterations but does not produce evidence of diarrheal disease in mice infected by the oral route. This study of EPEC experimental infection provides a better understanding of the effects of antibodies on bacterial infections and may provide a suitable model for the design and testing of immunobiological products for active or passive immunization.
authors.affiliation: Immunogenetics Laboratory, Butantan Institute.
authors.forename: Amanda Bardella
authors.initials: AB
authors.lastname: Vulcano
authors.forename: Milene
authors.initials: M
authors.lastname: Tino-De-Franco
authors.forename: José Araujo
authors.initials: JA
authors.lastname: Amaral
authors.forename: Orlando Garcia
authors.initials: OG
authors.lastname: Ribeiro
authors.forename: Wafa Hanna Koury
authors.initials: WH
authors.lastname: Cabrera
authors.forename: Marcela Aparecida
authors.initials: MA
authors.lastname: Bordenalli
authors.forename: Cristiane Barros
authors.initials: CB
authors.lastname: Carbonare
authors.forename: Eliana Parisi
authors.initials: EP
authors.lastname: Álvares
authors.forename: Solange Barros
authors.initials: SB
authors.lastname: Carbonare
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis / Q000097:blood; D057138:Bacterial Shedding; D001835:Body Weight; D004195:Disease Models, Animal; D054308:Enteropathogenic Escherichia coli / Q000276:immunology*; D004927:Escherichia coli Infections / Q000276:immunology* / Q000473:pathology*; D005260:Female; D006651:Histocytochemistry; D007413:Intestinal Mucosa / Q000382:microbiology* / Q000473:pathology*; D008297:Male; D051379:Mice; D008854:Microscopy, Electron
chemical_list: D000907:Antibodies, Bacterial
keywords: anti-Enteropathogenic Escherichia coli; antibodies; enteropathogenic Escherichia coli; experimental infection; selected mouse lines