title: Treatment of HeLa cells with bacterial water extracts inhibits Shigella flexneri invasion.
abstract: Pathogenesis mediated by Shigella flexneri requires invasion of the gastrointestinal epithelium. It has been previously shown that HeLa cells challenged with S. flexneri show alterations in their phosphotyrosine-containing protein profile. In this report, we demonstrated that bacterial water extracts (WE) abrogated the invasion of HeLa cells by S. flexneri in a dose-dependent manner. A proteinaceous component of S. flexneri was shown to be responsible for this inhibitory activity. Proteins encoded on the 140-MDa plasmid were not responsible for the observed inhibition. WE from other Gram-negative bacteria also inhibited Shigella invasion of HeLa cells pretreated with WE showed changes in the profile and the intensity of phosphotyrosine-containing protein bands. These data were consistent with a surface protein component in WE which initiated aberrant host cell signaling at the membrane which may account for the inhibition of bacterial entry.
authors.affiliation: Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston 77555-1019, USA.
authors.forename: B B
authors.initials: BB
authors.lastname: DiNovo
authors.forename: R
authors.initials: R
authors.lastname: Doan
authors.forename: R B
authors.initials: RB
authors.lastname: Dyer
authors.forename: S
authors.initials: S
authors.lastname: Baron
authors.forename: N K
authors.initials: NK
authors.lastname: Herzog
authors.forename: D W
authors.initials: DW
authors.lastname: Niesel
mesh_terms: D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000502:physiology*; D004755:Enterobacteriaceae / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000502:physiology*; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D010957:Plasmids; D012763:Shigella flexneri / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity* / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D019000:Phosphotyrosine