Cytochemical study of Streptococcus agalactiae and macrophage interaction

Abstract. Group B Streptococcus (GBS), a human pathogen that causes infection and invasive diseases in newborns, pregnant women and immunocompromised adults, has been shown to invade human umbilical vein endothelial cells (HUVECs). The objective of this study was to investigate the molecular mechanisms underlying GBS-HUVEC interaction, focusing specifically on the responsiveness of host protein tyrosine kinase (PTK). We found that GBS serotypes III and V induced actin reorganization and formation of stress fibers into HUVECs. Since rearrangements of the actin cytoskeleton into eukaryotic cells are usually associated with the activation of PTK, we decided to follow the expression of this class of kinases in the course of the interaction. Unexpectedly, treatment of HUVECs with genistein greatly increased both cytoadherence and intracellular viability, for all GBS strains studied. GBS increased tyrosine phosphorylation of two proteins with an apparent molecular mass of 35 and 23 kDa in HUVECs as demonstrated by Western blot analysis with antiphosphotyrosine antibodies. Mass spectra analysis identified these proteins as annexin V and glutathione S-transferase. Studies are in progress to identify the role of these two proteins on GBS-HUVEC interaction.

Section: Methodsmentioning

confidence: 99%

Section: ------------------------------------------------------------mentioning

confidence: 99%

Group B Streptococcus induces tyrosine phosphorylation of annexin V and glutathione S-transferase in human umbilical vein endothelial cells

Santos

Penha²,

Mattos‐Guaraldi³

et al. 2009

“…Subsequently, infected HUVECs were washed and treated with 200 μl M199 with orange acridine, re-incubated for 20 min at 37˚C/5% CO 2 and washed with M199 without orange acridine. The presence of orangestained GBS was considered indicative of the GBS-containing vacuole acidification (confocal laser scanning microscopy (CLSM Zeiss 310) (12).…”

Section: Gbs -Cfu Intracellular Gbs] (9)mentioning

confidence: 99%

Fever temperature enhances mechanisms of survival of Streptococcus agalactiae within human endothelial cells

Lione

Santos²,

Carvalho³

et al. 2010

Abstract. Group B streptococci (GBS) are the most common cause of pneumonia and sepsis during the neonatal period. However, the pathogenesis of invasive infection is poorly understood. We investigated the ability of GBS grown at 37˚C and 40˚C to adhere and invade human umbilical vein endothelial cells (HUVECs) at different periods of incubation (0, 0.5, 1, 2, 18 and 24 h). All strains tested, except strain 88641-vagina survived for 24 h in the intracellular environment at 40˚C. For serotype III grown at 40˚C, both strains (80340-vagina and 90356-liquor) showed increased adherence and intracellular survival when compared to bacteria grown at 37˚C (P<0.01). GBS serotype V strains (88641-vagina and 90186-blood) showed ability to survive inside HUVECs until 2 and 24 h post-infection at 40˚C and 37˚C, respectively (P<0.01). Influence of growth temperature in bacterial interaction with endothelial cells was partially dependent of serotypes and the clinical origin of strains. Serotypes III and V strains grown at both temperatures remained viable within acidic endothelial vacuoles which acquired Rab7 and LAMP-1 endosomal markers. The data emphasize the influence of temperature on cellular events of phagocytosis and pathogenesis of GBS diseases.

“…Monolayers were post-fixed with 1% OsO 4 , 5 mM CaCl 2 and 0.8% K 4 [Fe(CN 6 )] in cacodylate buffer for 1 h at 22˚C, and dehydrated through a series of graded ethanol solutions and embedded in Epon. Ultra-thin sections were examined under Zeiss EM 906 transmission electron microscope (Zeiss, Oberkochen, Germany) (20).…”

Section: Transmission Electron Microscopy (Tem)mentioning

confidence: 99%

Intracellular viability in human non-polarized respiratory epithelial 16 HBE 14o- cells by group B Streptococcus serotype III clinical isolates presenting 162-kb and 183-kb virulence markers

José

Miyazaki²,

Hirata³

et al. 2006

Abstract. Group B streptococci (GBS), mainly serotype III, are the major cause of neonatal pneumonia, sepsis and meningitis. Virulence potential of GBS strains may determine the outcome of host colonization or infection. Because the lung constitutes a first step in GBS systemic invasion processes, we investigated the adherence and invasion mechanisms of GBS-III clinical isolates to non-polarized human bronchial epithelial 16 HBE 14o-cell line. The presence of genotypic 162-kb and 183-kb virulence markers in all strains was also examined by PFGE. The 162-kb fragment was detected in both liquor (GBS-III 90356) and vagina (GBS-III 39A) isolates, while 183-kb fragment was only observed in strains (GBS-III 39A, 89A, and 80340) isolated from vagina of asymptomatic carriers. The actin-dependent ability to internalize within nonpolarized epithelial respiratory cells was demonstrated only by GBS-III clinical isolates presenting the 162-kb virulence marker. GBS-III 39A strain isolated from vagina exhibiting both 183-kb and 162-kb fragments showed a more efficient adherence and invasion properties than GBS-III 90356 isolated from liquor (P<0.001). Our data suggest the expression of additional bacterial virulence factors that may favor adherence and survival to non-polarized respiratory epithelial cells with consequent development of systemic diseases by GBS-III, including some strains isolated from asymptomatic carriers.