A capsular polysaccharide-specific antibody alters Streptococcus pneumoniae gene expression during nasopharyngeal colonization of mice
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PROVIDER: PRJNA454809 | ENA |
REPOSITORIES: ENA
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Project description:The bacterial cell envelope is a complex, multilayered structure that is not only essential to maintain cellular integrity, but also facilitates vital bacterial processes such as adaption, colonization and adhesion. Cell envelopes comprise a wide range of molecules, such as proteins and capsular polysaccharide (CPS), which collectively decorate the bacterial cell in a species- and strain specific manner. Here we characterized the 4 CPS gene cluster of L. plantarum and assessed the impact on CPS (combinatorial) gene deletions on surface polysaccharide composition.
2011-12-23 | GSE34690 | GEO
Project description:The bacterial cell envelope is a complex, multilayered structure that is not only essential to maintain cellular integrity, but also facilitates vital bacterial processes such as adaption, colonization and adhesion. Cell envelopes comprise a wide range of molecules, such as proteins and capsular polysaccharide (CPS), which collectively decorate the bacterial cell in a species- and strain specific manner. Here we characterized the 4 CPS gene cluster of L. plantarum and assessed the impact on CPS (combinatorial) gene deletions on surface polysaccharide composition. individual KOs of the cps clusters and the combination of all four together were compared with the WT expression in a loop design. The KO of 1-3 was directly compared to the WT (dye swapped)
2011-12-23 | E-GEOD-34690 | biostudies-arrayexpress
Project description:The primary mechanism by which pneumococcal capsular polysaccharide-based vaccines are believed to mediate protection is by induction of serotype-specific opsonic antibodies that facilitate bacterial killing by phagocytes (opsonophagocytosis). However, antibodies that are protective against experimental pneumococcal pneumonia in mice but do not promote opsonophagocytic killing in vitro have also been identified 1-3. Such non-opsonic antibodies are associated with bacterial clearance in vivo, but the mechanism by which this occurs is unknown. In this letter, we demonstrate that a protective, non-opsonic serotype 3 pneumococcal capsular polysaccharide-specific monoclonal antibody (MAb) enhances quorum sensing, which results in competence induction and fratricide of serotype 3 pneumococcus. Gene expression profile analysis revealed that the MAb together with the pneumococcal autoinducer, competence stimulating peptide 2 (CSP2), augments differential expression of competence (com) related bacteriocin-like peptide (blp) genes that are known to be involved in pneumococcal fratricide. Taken together, these findings reveal a previously unsuspected mechanism of antibody action, namely, enhancement of quorum sensing and bacterial fratricide. Given that this activity does not require phagocytes, antibodies that function accordingly may hold promise as adjuncts to current vaccines or as desired products of next generation pneumococcal vaccines. 6 samples
2011-03-01 | E-GEOD-27258 | biostudies-arrayexpress
Project description:The primary mechanism by which pneumococcal capsular polysaccharide-based vaccines are believed to mediate protection is by induction of serotype-specific opsonic antibodies that facilitate bacterial killing by phagocytes (opsonophagocytosis). However, antibodies that are protective against experimental pneumococcal pneumonia in mice but do not promote opsonophagocytic killing in vitro have also been identified 1-3. Such non-opsonic antibodies are associated with bacterial clearance in vivo, but the mechanism by which this occurs is unknown. In this letter, we demonstrate that a protective, non-opsonic serotype 3 pneumococcal capsular polysaccharide-specific monoclonal antibody (MAb) enhances quorum sensing, which results in competence induction and fratricide of serotype 3 pneumococcus. Gene expression profile analysis revealed that the MAb together with the pneumococcal autoinducer, competence stimulating peptide 2 (CSP2), augments differential expression of competence (com) related bacteriocin-like peptide (blp) genes that are known to be involved in pneumococcal fratricide. Taken together, these findings reveal a previously unsuspected mechanism of antibody action, namely, enhancement of quorum sensing and bacterial fratricide. Given that this activity does not require phagocytes, antibodies that function accordingly may hold promise as adjuncts to current vaccines or as desired products of next generation pneumococcal vaccines.
2011-03-01 | GSE27258 | GEO
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Project description:Diagnostic primer extension assay to serotype Streptococcus pneumoniae. Assay validation. Background: Monitoring of Streptococcus pneumoniae serotype epidemiology is essential since serotype replacement is a concern when introducing new polysaccharide-conjugate vaccines. To simplify S. pneumoniae serotyping, a novel PCR-based automated microarray assay was developed to assist in the tracking of the serotypes. Results: Autolysin (lytA), pneumolysin (ply) and eight genes located in the capsular operon (cps) were amplified using multiplex PCR. This step was followed by a tagged fluorescent primer extension step targeting serotype-specific polymorphisms. The tagged primers were then hybridized to a microarray. Results were exported to an expert system that transforms genetic typing data into capsular serotype identification. The assay was validated on 166 cultured S. pneumoniae samples from 63 different serotypes as determined by the Quellung method. In addition, the assay was tested on clinical specimens including 43 cerebrospinal fluid samples from patients with meningitidis and 59 nasopharyngeal aspirates from bacterial pneumonia patients. The assay presented with no cross-reactivity for 24 relevant bacterial species found in these types of samples. The limit of detection for serotyping and S. pneumoniae detection was 100 genome equivalent per reaction. Conclusion: This automated assay is amenable to clinical testing and does not require any culturing of the samples. The assay will be useful for the evaluation of serotype prevalence changes after new conjugate vaccines introduction. 166 quellung serotyped strains and two negative controls
2013-12-31 | E-GEOD-45865 | biostudies-arrayexpress
Project description:Diagnostic primer extension assay to serotype Streptococcus pneumoniae. Assay validation. Background: Monitoring of Streptococcus pneumoniae serotype epidemiology is essential since serotype replacement is a concern when introducing new polysaccharide-conjugate vaccines. To simplify S. pneumoniae serotyping, a novel PCR-based automated microarray assay was developed to assist in the tracking of the serotypes. Results: Autolysin (lytA), pneumolysin (ply) and eight genes located in the capsular operon (cps) were amplified using multiplex PCR. This step was followed by a tagged fluorescent primer extension step targeting serotype-specific polymorphisms. The tagged primers were then hybridized to a microarray. Results were exported to an expert system that transforms genetic typing data into capsular serotype identification. The assay was validated on 166 cultured S. pneumoniae samples from 63 different serotypes as determined by the Quellung method. In addition, the assay was tested on clinical specimens including 43 cerebrospinal fluid samples from patients with meningitidis and 59 nasopharyngeal aspirates from bacterial pneumonia patients. The assay presented with no cross-reactivity for 24 relevant bacterial species found in these types of samples. The limit of detection for serotyping and S. pneumoniae detection was 100 genome equivalent per reaction. Conclusion: This automated assay is amenable to clinical testing and does not require any culturing of the samples. The assay will be useful for the evaluation of serotype prevalence changes after new conjugate vaccines introduction.
2013-12-31 | GSE45865 | GEO
Project description: Not available
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Project description:Increasing evidence suggests that antibodies (Abs) can have protective roles in M. tuberculosis (Mtb) infection but knowledge of the most relevant protective antigens and epitopes in humans is limited. Using novel glycan arrays, we establish that human serum IgG induced against the M. tuberculosis (Mtb) capsular polysacharide arabinomannan (AM) in natural Mtb infection is highly heterogeneous in its binding specificity and differs in both its reactivity to oligosaccharide (OS) motifs within AM and its functions between BCG vaccination and/or controlled (latent) versus uncontrolled (TB) M. tuberculosis infection. We show that anti-AM IgG from asymptomatic but not diseased individuals is protective, and provide data suggesting a role of IgG2 and specific AM oligosaccharides. Filling a gap in the current knowledge of protective antigens in humans, our human data support the key role of the M. tuberculosis surface glycan AM and suggest the importance of targeting specific glycan epitopes within AM in antibody-mediated immunity against TB.
2019-12-10 | GSE141679 | GEO