title: The effects of interferon-gamma and transforming growth factor-beta on adherence and survival of group B Streptococcus type III strains in ECV304 cells.
abstract: Group B streptococci (GBS) are an important cause of neonatal sepsis, pneumonia and meningitis. In some newborns, GBS sepsis may have a severe course, including septic shock with high mortality rate, whereas other newborns are colonized with GBS on their surfaces without any clinical signs of bacterial infections. Interferon (IFN)-gamma is produced in neonatal GBS sepsis, and transforming growth factor (TGF)-beta is also found in the uterus. The involvement of IFN-gamma and TGF-beta in the earliest phase of infection might be a determinant of susceptibility and/or progression of infection in vivo. The aim of this study was to assess the effect of IFN-gamma and TGF-beta on adherence and intracellular viability in ECV304 cells of GBS serotype III isolated from cerebrospinal fluid (CSF) and vagina (strains 90356 and 80340, respectively). Interaction of GBS-ECV304 cells showed that the CSF isolate exhibited a more efficient adherence mechanism than the vagina isolate (P<0.001). Intracellular viability was observed for the CSF 90356 isolate within 2 h incubation. Results suggest the expression of additional bacterial virulence factors that favor some GBS type III strains to cause invasive disease. Detection of genotypic virulence marker (162-kb) in the CSF 90356 isolate by PFGE emphasizes the high risk of invasive infection by some GBS-III strains. Treatment of ECV304 cells with IFN-gamma and/or TGF-beta increased adherence of both GBS strains (P<0.001). Intracellular survival of the CSF 90356 isolate was observed after 24 h incubation following treatment of ECV304 cells with IFN-gamma and TGF-beta. Our data suggest that both IFN-gamma and TGF-beta may favor virulence of GBS strains. Variation of IFN-gamma and TGF-beta producing capacity of host cells of different individuals may influence development of invasive disease by GBS-III.
authors.affiliation: Disciplina de Microbiologia e Imunologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Vila Isabel, Rio de Janeiro, RJ 20.551-030, Brazil.
authors.forename: Gabriela S
authors.initials: GS
authors.lastname: Santos
authors.forename: Neide H T
authors.initials: NH
authors.lastname: Miyazaki
authors.forename: Ana Luiza
authors.initials: AL
authors.lastname: Mattos-Guaraldi
authors.forename: Prescilla E
authors.initials: PE
authors.lastname: Nagao
mesh_terms: D001422:Bacterial Adhesion / Q000187:drug effects*; D002353:Carrier State / Q000382:microbiology; D002478:Cells, Cultured; D002555:Cerebrospinal Fluid / Q000382:microbiology; D004730:Endothelium, Vascular / Q000166:cytology; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007371:Interferon-gamma / Q000494:pharmacology*; D013290:Streptococcal Infections / Q000209:etiology*; D013292:Streptococcus agalactiae; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D014472:Umbilicus / Q000098:blood supply; D014621:Vagina / Q000382:microbiology; D014680:Veins / Q000166:cytology
chemical_list: D016212:Transforming Growth Factor beta; D007371:Interferon-gamma