title: The flagella of an atypical enteropathogenic Escherichia coli strain are required for efficient interaction with and stimulation of interleukin-8 production by enterocytes in vitro.
abstract: The ability of some typical enteropathogenic Escherichia coli (EPEC) strains to adhere to, invade, and increase interleukin-8 (IL-8) production in intestinal epithelial cells in vitro has been demonstrated. However, few studies regarding these aspects have been performed with atypical EPEC (aEPEC) strains, which are emerging enteropathogens in Brazil. In this study, we evaluated a selected aEPEC strain (1711-4) of serotype O51:H40, the most prevalent aEPEC serotype in Brazil, in regard to its ability to adhere to and invade Caco-2 and T84 cells and to elicit IL-8 production in Caco-2 cells. The role of flagella in aEPEC 1711-4 adhesion, invasion, and IL-8 production was investigated by performing the same experiments with an isogenic aEPEC mutant unable to produce flagellin (FliC), the flagellum protein subunit. We demonstrated that this mutant (fliC mutant) had a marked decrease in the ability to adhere to T84 cells and invade both T84 and Caco-2 cells in gentamicin protection assays and by transmission electron microscopy. In addition, the aEPEC 1711-4 fliC mutant had a reduced ability to stimulate IL-8 production by Caco-2 cells in early (3-h) but not in late (24-h) infections. Our findings demonstrate that flagella of aEPEC 1711-4 are required for efficient adhesion, invasion, and early but not late IL-8 production in intestinal epithelial cells in vitro.
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu 862, 3 degrees andar, 04023-062 São Paulo, Brazil.
authors.forename: Suely C F
authors.initials: SC
authors.lastname: Sampaio
authors.forename: Tânia A T
authors.initials: TA
authors.lastname: Gomes
authors.forename: Christophe
authors.initials: C
authors.lastname: Pichon
authors.forename: Laurence
authors.initials: L
authors.lastname: du Merle
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Guadagnini
authors.forename: Cecilia M
authors.initials: CM
authors.lastname: Abe
authors.forename: Jorge L M
authors.initials: JL
authors.lastname: Sampaio
authors.forename: Chantal
authors.initials: C
authors.lastname: Le Bouguénec
mesh_terms: D001422:Bacterial Adhesion; D001938:Brazil; D002460:Cell Line; D015169:Colony Count, Microbial; D003593:Cytoplasm / Q000382:microbiology; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D020895:Enterocytes / Q000276:immunology* / Q000382:microbiology*; D054308:Enteropathogenic Escherichia coli / Q000276:immunology* / Q000302:isolation & purification / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics; D005407:Flagella / Q000502:physiology*; D005408:Flagellin; D017353:Gene Deletion; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism*; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C516095:FliC protein, E coli; D016209:Interleukin-8; D005408:Flagellin