title: Group B Streptococcus crosses human epithelial cells by a paracellular route.
abstract: Colonization of the colon and vagina is thought to be important in the pathogenesis of group B Streptococcus (GBS) infection. However, little is known about the strategies used by GBS to translocate through the epithelial barrier during the onset of disease. We used differentiated epithelial cells grown on transwell inserts as a model of the epithelial barrier. Bacterial translocation occurred without a detectable decrease in transepithelial resistance. Whereas acapsular GBS was better able to adhere to and invade epithelial cells, the percentage of bacteria translocating across the epithelial monolayer was independent of the presence of the capsule. Transmission electron microscopy showed the intimate association of GBS with intercellular junctions and the capacity to cross the monolayer by a paracellular mechanism. This process consisted of an active and transient opening of cell junctions. Indeed, GBS was preferentially found along the cell perimeter, where it colocalized with junctional protein complexes.
authors.affiliation: Immunobiological Research Institute of Siena (IRIS), Chiron Vaccines, Siena, Italy. marco_soriani@chiron.com
authors.forename: Marco
authors.initials: M
authors.lastname: Soriani
authors.forename: Isabella
authors.initials: I
authors.lastname: Santi
authors.forename: Annarita
authors.initials: A
authors.lastname: Taddei
authors.forename: Rino
authors.initials: R
authors.lastname: Rappuoli
authors.forename: Guido
authors.initials: G
authors.lastname: Grandi
authors.forename: John L
authors.initials: JL
authors.lastname: Telford
mesh_terms: D016667:Bacterial Capsules / Q000502:physiology; D002460:Cell Line; D004847:Epithelial Cells / Q000382:microbiology* / Q000648:ultrastructure; D004848:Epithelium / Q000382:microbiology* / Q000648:ultrastructure; D006801:Humans; D007120:Immunochemistry; D007365:Intercellular Junctions / Q000382:microbiology / Q000648:ultrastructure; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D013292:Streptococcus agalactiae / Q000502:physiology*