Publications by authors named "Angela Spagnuolo"

5 Publications

  • Page 1 of 1

Protective effect of Group B Streptococcus type-III polysaccharide conjugates against maternal colonization, ascending infection and neonatal transmission in rodent models.

Sci Rep 2018 02 7;8(1):2593. Epub 2018 Feb 7.

GSK, Siena, Italy.

Group B Streptococcus (GBS) is a normal inhabitant of recto-vaginal mucosae in up to 30% of healthy women. Colonization is a major risk factor for perinatal infection which can lead to severe complications such as stillbirth and neonatal invasive disease. Intra-partum antibiotic prophylaxis in colonized women is a safe and cost-effective preventive measure against early-onset disease in the first days of life, but has no effect on late-onset manifestations or on early maternal infection. Maternal immunization with capsular polysaccharide-based vaccines shows promise for the prevention of both early-onset and late-onset neonatal infections, although ability to prevent maternal colonization and ascending infection has been less studied. Here we investigated the effect of a GBS glycoconjugate vaccine since the very early stage of maternal GBS acquisition to neonatal outcome by rodent models of vaginal colonization and ascending infection. Immunization of female mice and rats with a type III glycoconjugate reduced vaginal colonization, infection of chorioamniotic/ placental membranes and bacterial transmission to fetuses and pups. Type III specific antibodies were detected in the blood and vagina of vaccinated mothers and their offspring. The obtained data support a potential preventive effect of GBS glycoconjugate vaccines during the different stages of pregnancy.
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http://dx.doi.org/10.1038/s41598-018-20609-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5803199PMC
February 2018

Development of a Click Beetle Luciferase Reporter System for Enhanced Bioluminescence Imaging of : Analysis in Cell Culture and Murine Infection Models.

Front Microbiol 2017 26;8:1797. Epub 2017 Sep 26.

APC Microbiome Institute, University College Cork, Cork, Ireland.

is a Gram-positive facultative intracellular pathogen that is widely used as a model organism for the analysis of infection biology. In this context, there is a current need to develop improved reporters for enhanced bioluminescence imaging (BLI) of the pathogen in infection models. We have developed a click beetle red luciferase (CBR-) based vector (pPL2CBR) expressing codon optimized CBR- under the control of a highly expressed Listerial promoter (P) for and have compared this to a -based system expressing bacterial luciferase for BLI of the pathogen using growth experiments and models. The CBR- plasmid stably integrates into the chromosome and can be used to label field isolates and laboratory strains of the pathogen. Growth experiments revealed that CBR- labeled emits a bright signal in exponential phase that is maintained during stationary phase. In contrast, -labeled bacteria produced a light signal that peaked during exponential phase and was significantly reduced during stationary phase. Light from CBR- labeled bacteria was more efficient than the signal from -labeled bacteria in penetrating an artificial tissue depth assay system. A cell invasion assay using C2Bbe1 cells and a systemic murine infection model revealed that CBR- is suited to BLI approaches and demonstrated enhanced sensitivity relative to in the context of infection models. Overall, we demonstrate that this novel CBR reporter system provides efficient, red-shifted light production relative to and may have significant applications in the analysis of pathogenesis.
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http://dx.doi.org/10.3389/fmicb.2017.01797DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5622934PMC
September 2017

SslE elicits functional antibodies that impair in vitro mucinase activity and in vivo colonization by both intestinal and extraintestinal Escherichia coli strains.

PLoS Pathog 2014 May 8;10(5):e1004124. Epub 2014 May 8.

Novartis Vaccines and Diagnostics Srl, Siena, Italy.

SslE, the Secreted and surface-associated lipoprotein from Escherichia coli, has recently been associated to the M60-like extracellular zinc-metalloprotease sub-family which is implicated in glycan recognition and processing. SslE can be divided into two main variants and we recently proposed it as a potential vaccine candidate. By applying a number of in vitro bioassays and comparing wild type, knockout mutant and complemented strains, we have now demonstrated that SslE specifically contributes to degradation of mucin substrates, typically present in the intestine and bladder. Mutation of the zinc metallopeptidase motif of SslE dramatically impaired E. coli mucinase activity, confirming the specificity of the phenotype observed. Moreover, antibodies raised against variant I SslE, cloned from strain IHE3034 (SslEIHE3034), are able to inhibit translocation of E. coli strains expressing different variants through a mucin-based matrix, suggesting that SslE induces cross-reactive functional antibodies that affect the metallopeptidase activity. To test this hypothesis, we used well-established animal models and demonstrated that immunization with SslEIHE3034 significantly reduced gut, kidney and spleen colonization by strains producing variant II SslE and belonging to different pathotypes. Taken together, these data strongly support the importance of SslE in E. coli colonization of mucosal surfaces and reinforce the use of this antigen as a component of a broadly protective vaccine against pathogenic E. coli species.
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http://dx.doi.org/10.1371/journal.ppat.1004124DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4014459PMC
May 2014

Identification of protective and broadly conserved vaccine antigens from the genome of extraintestinal pathogenic Escherichia coli.

Proc Natl Acad Sci U S A 2010 May 3;107(20):9072-7. Epub 2010 May 3.

Novartis Vaccines and Diagnostics, 53100 Siena, Italy.

Extraintestinal pathogenic Escherichia coli (ExPEC) are a common cause of disease in both mammals and birds. A vaccine to prevent such infections would be desirable given the increasing antibiotic resistance of these bacteria. We have determined the genome sequence of ExPEC IHE3034 (ST95) isolated from a case of neonatal meningitis and compared this to available genome sequences of other ExPEC strains and a few nonpathogenic E. coli. We found 19 genomic islands present in the genome of IHE3034, which are absent in the nonpathogenic E. coli isolates. By using subtractive reverse vaccinology we identified 230 antigens present in ExPEC but absent (or present with low similarity) in nonpathogenic strains. Nine antigens were protective in a mouse challenge model. Some of them were also present in other pathogenic non-ExPEC strains, suggesting that a broadly protective E. coli vaccine may be possible. The gene encoding the most protective antigen was detected in most of the E. coli isolates, highly conserved in sequence and found to be exported by a type II secretion system which seems to be nonfunctional in nonpathogenic strains.
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http://dx.doi.org/10.1073/pnas.0915077107DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2889118PMC
May 2010

Proteomics characterization of outer membrane vesicles from the extraintestinal pathogenic Escherichia coli DeltatolR IHE3034 mutant.

Mol Cell Proteomics 2008 Mar 2;7(3):473-85. Epub 2007 Nov 2.

Biochemistry and Molecular Biology Unit, Novartis Vaccines and Diagnostics, 53100 Siena, Italy.

Extraintestinal pathogenic Escherichia coli are the cause of a diverse spectrum of invasive infections in humans and animals, leading to urinary tract infections, meningitis, or septicemia. In this study, we focused our attention on the identification of the outer membrane proteins of the pathogen in consideration of their important biological role and of their use as potential targets for prophylactic and therapeutic interventions. To this aim, we generated a DeltatolR mutant of the pathogenic IHE3034 strain that spontaneously released a large quantity of outer membrane vesicles in the culture supernatant. The vesicles were analyzed by two-dimensional electrophoresis coupled to mass spectrometry. The analysis led to the identification of 100 proteins, most of which are localized to the outer membrane and periplasmic compartments. Interestingly based on the genome sequences available in the current public database, seven of the identified proteins appear to be specific for pathogenic E. coli and enteric bacteria and therefore are potential targets for vaccine and drug development. Finally we demonstrated that the cytolethal distending toxin, a toxin exclusively produced by pathogenic bacteria, is released in association with the vesicles, supporting the recently proposed role of bacterial vesicles in toxin delivery to host cells. Overall, our data demonstrated that outer membrane vesicles represent an ideal tool to study Gram-negative periplasm and outer membrane compartments and to shed light on new mechanisms of bacterial pathogenesis.
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http://dx.doi.org/10.1074/mcp.M700295-MCP200DOI Listing
March 2008