scholarly journals The Putative Proteinase Maturation Protein A ofStreptococcus pneumoniae Is a Conserved Surface Protein with Potential To Elicit Protective Immune Responses

2000 ◽  
Vol 68 (7) ◽  
pp. 4180-4188 ◽  
Author(s):  
K. Overweg ◽  
A. Kerr ◽  
M. Sluijter ◽  
M. H. Jackson ◽  
T. J. Mitchell ◽  
...  
Keyword(s):  
Protein Fraction ◽  
Pathogenic Bacteria ◽  
Protein A ◽  
Surface Protein ◽  
Cross Reactivity ◽  
Two Dimensional Gel Electrophoresis ◽  
Hyperimmune Serum ◽  
Maturation Protein ◽  
Species Specific

ABSTRACT Surface-exposed proteins often play an important role in the interaction between pathogenic bacteria and their host. We isolated a pool of hydrophobic, surface-associated proteins of Streptococcus pneumoniae. The opsonophagocytic activity of hyperimmune serum raised against this protein fraction was high and species specific. Moreover, the opsonophagocytic activity was independent of the capsular type and chromosomal genotype of the pneumococcus. Since the opsonophagocytic activity is presumed to correlate with in vivo protection, these data indicate that the protein fraction has the potential to elicit species-specific immune protection with cross-protection against various pneumococcal strains. Individual proteins in the extract were purified by two-dimensional gel electrophoresis. Antibodies raised against three distinct proteins contributed to the opsonophagocytic activity of the serum. The proteins were identified by mass spectrometry and N-terminal amino acid sequencing. Two proteins were the previously characterized pneumococcal surface protein A and oligopeptide-binding lipoprotein AmiA. The third protein was the recently identified putative proteinase maturation protein A (PpmA), which showed homology to members of the family of peptidyl-prolyl cis/trans isomerases. Immunoelectron microscopy demonstrated that PpmA was associated with the pneumococcal surface. In addition, PpmA was shown to elicit species-specific opsonophagocytic antibodies that were cross-reactive with various pneumococcal strains. This antibody cross-reactivity was in line with the limited sequence variation of ppmA. The importance of PpmA in pneumococcal pathogenesis was demonstrated in a mouse pneumonia model. Pneumococcal ppmA-deficient mutants showed reduced virulence. The properties of PpmA reported here indicate its potential for inclusion in multicomponent protein vaccines.

scholarly journals Comparative Secretome Analyses of Three Bacillus anthracis Strains with Variant Plasmid Contents

2005 ◽  
Vol 73 (6) ◽  
pp. 3646-3658 ◽  
Author(s):  
Janine M. Lamonica ◽  
MaryAnn Wagner ◽  
Michel Eschenbrenner ◽  
Leanne E. Williams ◽  
Tabbi L. Miller ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Protective Antigen ◽  
Isocitrate Lyase ◽  
Lethal Factor ◽  
Protein A ◽  
Surface Protein ◽  
Computer Assisted ◽  
Two Dimensional Gel Electrophoresis ◽  
Peptide Mass ◽  
Proteomic Approach

ABSTRACT Bacillus anthracis, the causative agent of anthrax, secretes numerous proteins into the extracellular environment during infection. A comparative proteomic approach was employed to elucidate the differences among the extracellular proteomes (secretomes) of three isogenic strains of B. anthracis that differed solely in their plasmid contents. The strains utilized were the wild-type virulent B. anthracis RA3 (pXO1+ pXO2+) and its two nonpathogenic derivative strains: the toxigenic, nonencapsulated RA3R (pXO1+ pXO2−) and the totally cured, nontoxigenic, nonencapsulated RA3:00 (pXO1− pXO2−). Comparative proteomics using two-dimensional gel electrophoresis followed by computer-assisted gel image analysis was performed to reveal unique, up-regulated, or down-regulated secretome proteins among the strains. In total, 57 protein spots, representing 26 different proteins encoded on the chromosome or pXO1, were identified by peptide mass fingerprinting. S-layer-derived proteins, such as Sap and EA1, were most frequently observed. Many sporulation-associated enzymes were found to be overexpressed in strains containing pXO1+. This study also provides evidence that pXO2 is necessary for the maximal expression of the pXO1-encoded toxins lethal factor (LF), edema factor (EF), and protective antigen (PA). Several newly identified putative virulence factors were observed; these include enolase, a high-affinity zinc uptake transporter, the peroxide stress-related alkyl hydroperoxide reductase, isocitrate lyase, and the cell surface protein A.

scholarly journals Recognition of pneumococcal isolates by antisera raised against PspA fragments from different clades

2008 ◽  
Vol 57 (3) ◽  
pp. 273-278 ◽  
Author(s):  
Michelle Darrieux ◽  
Adriana T. Moreno ◽  
Daniela M. Ferreira ◽  
Fabiana C. Pimenta ◽  
Ana Lúcia S. S. de Andrade ◽  
...  
Keyword(s):  
Animal Models ◽  
Vaccine Candidate ◽  
Protein A ◽  
Surface Protein ◽  
Structural Diversity ◽  
Cross Reactivity ◽  
Terminal Region ◽  
Hybrid Protein ◽  
Pneumococcal Infections ◽  
Clade 1

Pneumococcal surface protein A (PspA) is an important vaccine candidate against pneumococcal infections, capable of inducing protection in different animal models. Based on its structural diversity, it has been suggested that a PspA-based vaccine should contain at least one fragment from each of the two major families (family 1, comprising clades 1 and 2, and family 2, comprising clades 3, 4 and 5) in order to elicit broad protection. This study analysed the recognition of a panel of 35 pneumococcal isolates bearing different PspAs by antisera raised against the N-terminal regions of PspA clades 1 to 5. The antiserum to PspA clade 4 was found to show the broadest cross-reactivity, being able to recognize pneumococcal strains containing PspAs of all clades in both families. The cross-reactivity of antibodies elicited against a PspA hybrid including the N-terminal region of clade 1 fused to a shorter and more divergent fragment (clade-defining region, or CDR) of clade 4 (PspA1–4) was also tested, and revealed a strong recognition of isolates containing clades 1, 4 and 5, and weaker reactions with clades 2 and 3. The analysis of serum reactivity against different PspA regions further revealed that the complete N-terminal region rather than just the CDR should be included in an anti-pneumococcal vaccine. A PspA-based vaccine is thus proposed to be composed of the whole N-terminal region of clades 1 and 4, which could also be expressed as a hybrid protein.

scholarly journals Identification of the Targets of Cross-Reactive Antibodies Induced by Streptococcus pneumoniae Colonization

2010 ◽  
Vol 78 (5) ◽  
pp. 2231-2239 ◽  
Author(s):  
Aoife M. Roche ◽  
Jeffrey N. Weiser
Keyword(s):  
Streptococcus Pneumoniae ◽  
Protein A ◽  
Surface Protein ◽  
Wild Type ◽  
Modest Contribution ◽  
Heterologous Challenge ◽  
Human Sera ◽  
Maturation Protein ◽  
Type Strains ◽  
Major Target

ABSTRACTMuch of the efficacy of current pneumococcal conjugate vaccines lies in their ability to decrease carriage of vaccine serotypes in the population. Novel and more-broadly acting vaccines would also need to target carriage in order to be as effective. We have previously shown that model murine carriage ofStreptococcus pneumoniaecan elicit antibody-dependent immunity and can protect against a virulent heterologous challenge strain. This study set out to identifyS. pneumoniaesurface antigens that may elicit cross-reactive antibodies following colonization. Western blot analysis using sera from colonized mice identified the previously characterized immunogens pneumococcal surface protein A (PspA), putative proteinase maturation protein A (PpmA), and pneumococcal surface adhesin A (PsaA) as such antigens. Using flow cytometry, PspA was found to be the major target of surface-bound cross-reactive IgG in sera from TIGR4Δcps-colonized mice, with a modest contribution from PpmA and none from PsaA. In human sera, however, only mutants lacking PpmA were shown to have reduced binding of surface IgG compared to wild-type strains, suggesting that prior exposure toS. pneumoniaein humans may induce PpmA antibodies. We also investigated if cross-reactive antibodies induced by these antigens may be cross-protective against carriage. Despite the immunogenicity of PspA, PpmA, and PsaA, mice were still protected following colonization with mutants lacking these antigens, suggesting they are not necessary for cross-protection induced by carriage. Our findings suggest that a whole-organism approach may be needed to broadly diminish carriage.

scholarly journals PneumococcalSurface Protein A Is Expressed In Vivo, and Antibodies to PspA AreEffective for Therapy in a Murine Model of PneumococcalSepsis

2003 ◽  
Vol 71 (12) ◽  
pp. 7149-7153 ◽  
Author(s):  
E. Swiatlo ◽  
J. King ◽  
G. S. Nabors ◽  
B. Mathews ◽  
D. E. Briles
Keyword(s):  
Northern Blot Analysis ◽  
Lethal Dose ◽  
Protein A ◽  
Surface Protein ◽  
Immune Serum ◽  
Invasive Infection ◽  
Pneumococcal Infections ◽  
Type 3

ABSTRACT Pneumococcal surface protein A (PspA) is an immunogenic protein expressed on the surface of all strains of Streptococcus pneumoniae (pneumococcus) and induces antibodies which protect against invasive infection in mice. Pneumococci used for infectious challenge in protection studies are typically collected from cultures grown in semisynthetic medium in vitro. The purpose of these studies is to confirm that PspA is expressed by pneumococci during growth in vivo at a level sufficient for antibodies to PspA to be protective. Mice were actively immunized with purified PspA or by passive transfer of monoclonal antibody (MAb) and challenged with a capsular type 3 strain in diluted whole blood from bacteremic mice. All were protected against challenge with 10 times the 50% lethal dose (LD50), and mice challenged with 1,000 times the LD50 had increased survival compared with controls. Additionally, nonimmune mice treated with MAbs to PspA or PspA immune serum at 6 and 12 h after infection with 10 times the LD50 also showed increased survival. Northern blot analysis of RNA from pneumococci grown either in vitro or in vivo showed similar levels of PspA mRNA. These results demonstrate that PspA is expressed in vivo in a mouse model and that immunization with PspA induces antibodies to an antigen which is expressed during the course of invasive infection. Immunotherapy with antibodies to PspA may have some utility in treating pneumococcal infections in humans.

scholarly journals Host-Adapted Borrelia burgdorferi in Mice Expresses OspA during Inflammation

2003 ◽  
Vol 71 (7) ◽  
pp. 4003-4010 ◽  
Author(s):  
Helena Crowley ◽  
Brigitte T. Huber
Keyword(s):  
Borrelia Burgdorferi ◽  
Protein A ◽  
Surface Protein ◽  
Conclusive Evidence ◽  
Antibody Responses ◽  
In Vivo Model ◽  
Mammalian Host ◽  
Outer Surface Protein A ◽  
Reverse Transcription Pcr

ABSTRACT Antibody responses to outer surface protein A (OspA) of Borrelia burgdorferi may occur during periods of arthritis late in the clinical course of untreated Lyme disease. These antibody responses are paradoxical, given the conclusive evidence demonstrating that B. burgdorferi transmitted to the mammalian host expresses little or no OspA. The parallel occurrence of OspA antibodies and arthritic episodes suggests that OspA expression is upregulated during infection with B. burgdorferi. We hypothesized that this was due to the inflammatory environment caused by the immune response to the spirochete. To test our hypothesis, we adapted an in vivo model that mimics the host-pathogen interaction. Dialysis chambers containing B. burgdorferi were implanted into the peritoneal cavities of mice in the presence or absence of zymosan, a yeast cell wall extract that induces inflammation. Spirochetes were harvested 2 days later, and OspA expression was assessed at the protein and transcription level by Western blotting and real-time reverse transcription-PCR, respectively. Flow cytometry was also utilized to evaluate OspA protein expression on individual spirochetes. B. burgdorferi maintained in an inflammatory in vivo environment show an increased OspA expression relative to B. burgdorferi kept under normal in vivo conditions. Furthermore, host-adapted B. burgdorferi with a low OspA phenotype upregulates OspA expression when transferred to an inflammatory in vivo environment. The results obtained by these techniques uniformly identify inflammation as a mediator of in vivo OspA expression in host-adapted B. burgdorferi, providing insights into the behavior of live spirochetes in the mammalian host.

scholarly journals Conjugation of PspA4Pro with Capsular Streptococcus pneumoniae Polysaccharide Serotype 14 Does Not Reduce the Induction of Cross-Reactive Antibodies

2017 ◽  
Vol 24 (8) ◽  
Author(s):  
Míriam A. da Silva ◽  
Thiago R. Converso ◽  
Viviane M. Gonçalves ◽  
Luciana C. C. Leite ◽  
Martha M. Tanizaki ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Capsular Polysaccharide ◽  
Vaccine Coverage ◽  
Protein A ◽  
Surface Protein ◽  
Cross Reactivity ◽  
Carrier Protein ◽  
Content Type ◽  
Clade 1 ◽  
The Impact

ABSTRACT Current pneumococcal vaccines are composed of bacterial polysaccharides as antigens, plain or conjugated to carrier proteins. While efficacious against vaccine serotypes, epidemiologic data show an increasing incidence of infections caused by nonvaccine serotypes of Streptococcus pneumoniae. The use of pneumococcal surface protein A (PspA) as a carrier protein in a conjugate vaccine could help prevent serotype replacement by increasing vaccine coverage and reducing selective pressure of S. pneumoniae serotypes. PspA is present in all pneumococcal strains, is highly immunogenic, and is known to induce protective antibodies. Based on its sequence, PspA has been classified into three families and six clades. A PspA fragment derived from family 2, clade 4 (PspA4Pro), was shown to generate antibodies with a broad range of cross-reactivity, across clades and families. Here, PspA4Pro was modified and conjugated to capsular polysaccharide serotype 14 (PS14). We investigated the impact of conjugation on the immune response induced to PspA4Pro and PS14. Mice immunized with the PS14-mPspA4Pro conjugate produced higher titers of anti-PS14 antibodies than the animals that received coadministered antigens. The conjugate induced antibodies with opsonophagocytic activity against PS14-carrying strains, as well as against a panel of strains bearing PspAs from five clades (encompassing families 1 and 2) bearing a non-PS14 serotype. Furthermore, mice immunized with PS14-mPspA4Pro were protected against nasal colonization with a nonrelated S. pneumoniae strain bearing PspA from clade 1, serotype 6B. These results demonstrate that the cross-reactivity mediated by PspA4Pro is retained following conjugation, supporting the use of PspA4 as a carrier protein in order to enhance pneumococcal vaccine coverage and encourage its further investigation as a candidate in future vaccine designs.

scholarly journals The Proline-Rich Region of Pneumococcal Surface Proteins A and C Contains Surface-Accessible Epitopes Common to All Pneumococci and Elicits Antibody-Mediated Protection against Sepsis

2010 ◽  
Vol 78 (5) ◽  
pp. 2163-2172 ◽  
Author(s):  
Calvin C. Daniels ◽  
Patricia Coan ◽  
Janice King ◽  
Joanetha Hale ◽  
Kimberly A. Benton ◽  
...  
Keyword(s):  
Protein A ◽  
Pneumococcal Infection ◽  
Passive Immunization ◽  
Surface Protein ◽  
Helical Structure ◽  
Structural Similarity ◽  
Cross Reactivity ◽  
Surface Proteins ◽  
Structure Characteristic ◽  
Protective Antibodies

ABSTRACTPneumococcal surface protein A (PspA) and PspC ofStreptococcus pneumoniaeare surface virulence proteins that interfere with complement deposition and elicit protective immune responses. The C-terminal halves of PspA and PspC have some structural similarity and contain highly cross-reactive proline-rich (PR) regions. In many PR regions of PspA and PspC, there exists an almost invariant nonproline block (NPB) of about 33 amino acids. Neither the PR regions nor their NPB exhibit the alpha-helical structure characteristic of much of the protection-eliciting N-terminal portions of PspA and PspC. Prior studies of PspA and PspC as immunogens focused primarily on the alpha-helical regions of these molecules that lack the PR and NPB regions. This report shows that immunization with recombinant PR (rPR) molecules and passive immunization with monoclonal antibodies reactive with either NPB or PR epitopes are protective against infection in mice. PR regions of both PspA and PspC were antibody accessible on the pneumococcal surface. Our results indicate that while PspA could serve as a target of these protective antibodies in invasive infections, PspC might not. When antibody responses to rPR immunogens were evaluated by using flow cytometry to measure antibody binding to live pneumococci, it was observed that the mice that survived subsequent challenge produced significantly higher levels of antibodies reactive with exposed PR epitopes than the mice that became moribund. Due to their conservation and cross-reactivity, the PR regions and NPB regions represent potential vaccine targets capable of eliciting cross-protection immunity against pneumococcal infection.

scholarly journals Evidence for Vaccine Synergy between Borrelia burgdorferi Decorin Binding Protein A and Outer Surface Protein A in the Mouse Model of Lyme Borreliosis

2000 ◽  
Vol 68 (11) ◽  
pp. 6457-6460 ◽  
Author(s):  
Mark S. Hanson ◽  
Nita K. Patel ◽  
David R. Cassatt ◽  
Nancy D. Ulbrandt
Keyword(s):  
Borrelia Burgdorferi ◽  
Outer Surface ◽  
Binding Protein ◽  
Protein A ◽  
Surface Protein ◽  
Outer Surface Protein A ◽  
Outer Surface Protein ◽  
Antigen Vaccine ◽  
Single Antigen

ABSTRACT Mice immunized with either the predominantly vector-stage lipoprotein outer surface protein A (OspA) or the in vivo-expressed lipoprotein decorin binding protein A (DbpA) are protected againstBorrelia burgdorferi challenge. DbpA-OspA combinations protected against 100-fold-higher challenge doses than did either single-antigen vaccine and conferred significant protection against heterologous B. burgdorferi, B. garinii, andB. afzelii isolates, suggesting that there is synergy between these two immunogens.

scholarly journals Descriptive Comparison of ELISAs for the Detection of Toxoplasma gondii Antibodies in Animals: A Systematic Review

Pathogens ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 605
Author(s):  
K. L. D. Tharaka D. Liyanage ◽  
Anke Wiethoelter ◽  
Jasmin Hufschmid ◽  
Abdul Jabbar
Keyword(s):  
Systematic Review ◽  
Toxoplasma Gondii ◽  
Animal Species ◽  
Specific Binding ◽  
Protein A ◽  
Cross Reactivity ◽  
Meat Juice ◽  
Wide Range ◽  
Eimeria Spp ◽  
Species Specific

Toxoplasma gondii is the zoonotic parasite responsible for toxoplasmosis in warm-blooded vertebrates. This systematic review compares and evaluates the available knowledge on enzyme-linked immunosorbent assays (ELISAs), their components, and performance in detecting T. gondii antibodies in animals. Four databases were searched for published scientific studies on T. gondii and ELISA, and 57 articles were included. Overall, indirect (95%) and in-house (67%) ELISAs were the most used types of test among the studies examined, but the ‘ID Screen® Toxoplasmosis Indirect Multi-species’ was common among commercially available tests. Varying diagnostic performance (sensitivity and specificity) and Kappa agreements were observed depending on the type of sample (serum, meat juice, milk), antigen (native, recombinant, chimeric) and antibody-binding reagents used. Combinations of recombinant and chimeric antigens resulted in better performance than native or single recombinant antigens. Protein A/G appeared to be useful in detecting IgG antibodies in a wide range of animal species due to its non-species-specific binding. One study reported cross-reactivity, with Hammondia hammondi and Eimeria spp. This is the first systematic review to descriptively compare ELISAs for the detection of T. gondii antibodies across different animal species.

scholarly journals Genome-wide analysis of in vivo CcpA binding with and without its key co-factor HPr in the major human pathogen group A Streptococcus

2020 ◽  
Author(s):  
Sruti DebRoy ◽  
Victor Aliaga Tobar ◽  
Gabriel Galvez ◽  
Srishtee Arora ◽  
Xiaowen Liang ◽  
...  
Keyword(s):  
Dna Binding ◽  
Pathogenic Bacteria ◽  
Group A Streptococcus ◽  
Protein A ◽  
Data Availability ◽  
Human Pathogen ◽  
Transcript Levels ◽  
Catabolite Control Protein A ◽  
Group A

SummaryCatabolite control protein A (CcpA) is a master regulator of carbon source utilization and contributes to the virulence of numerous medically important Gram-positive bacteria. Most functional assessments of CcpA, including interaction with its key co-factor HPr, have been performed in non-pathogenic bacteria. In this study we aimed to identify the in vivo DNA binding profile of CcpA and assess the extent to which HPr is required for CcpA-mediated regulation and DNA binding in the major human pathogen group A Streptococcus (GAS). Using a combination RNAseq/ChIPseq approach, we found that CcpA affects transcript levels of 514 of 1667 GAS genes (31%) whereas direct DNA binding was identified for 105 GAS genes. Three of the directly regulated genes encode the key GAS virulence factors Streptolysin S, PrtS (IL-8 degrading proteinase), and SpeB (cysteine protease). Mutating CcpA Val301 to Ala (strain 2221-CcpA-V301A) abolished interaction between CcpA and HPr and impacted the transcript levels of 205 genes (40%) in the total CcpA regulon. By ChIPseq analysis, CcpAV301A bound to DNA from 74% of genes bound by wild-type CcpA, but generally with lower affinity. These data delineate the direct CcpA regulon and clarify the HPr-dependent and independent activities of CcpA in a key pathogenic bacterium.Data sharing and data availabilityThe data that support the findings of this study are available from the corresponding author upon reasonable request.

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