scholarly journals Relapsing Fever Spirochetes Borrelia recurrentis and B. duttonii Acquire Complement Regulators C4b-Binding Protein and Factor H

2006 ◽  
Vol 74 (7) ◽  
pp. 4157-4163 ◽  
Author(s):  
T. Meri ◽  
S. J. Cutler ◽  
A. M. Blom ◽  
S. Meri ◽  
T. S. Jokiranta
Keyword(s):  
Binding Protein ◽  
Protein A ◽  
Sensu Stricto ◽  
Factor H ◽  
Complement Pathway ◽  
Relapsing Fever ◽  
Borrelia Recurrentis ◽  
First Report ◽  
Complement Regulators

ABSTRACT Relapsing fever is a rapidly progressive and severe septic disease caused by certain Borrelia spirochetes. The disease is divided into two forms, i.e., epidemic relapsing fever, caused by Borrelia recurrentis and transmitted by lice, and the endemic form, caused by several Borrelia species, such as B. duttonii, and transmitted by soft-bodied ticks. The spirochetes enter the bloodstream by the vector bite and live persistently in plasma even after the development of specific antibodies. This leads to fever relapses and high mortality and clearly indicates that the Borrelia organisms utilize effective immune evasion strategies. In this study, we show that the epidemic relapsing fever pathogen B. recurrentis and an endemic relapsing fever pathogen, B. duttonii, are serum resistant, i.e., resistant to complement in vitro. They acquire the host alternative complement pathway regulator factor H on their surfaces in a similar way to that of the less serum-resistant Lyme disease pathogen, B. burgdorferi sensu stricto. More importantly, the relapsing fever spirochetes specifically bind host C4b-binding protein, a major regulator of the antibody-mediated classical complement pathway. Both complement regulators retained their functional activities when bound to the surfaces of the spirochetes. In conclusion, this is the first report of complement evasion by Borrelia recurrentis and B. duttonii and the first report showing capture of C4b-binding protein by spirochetes.

scholarly journals The Borrelia hermsii Factor H Binding Protein FhbA Is Not Required for Infectivity in Mice or for Resistance to Human ComplementIn Vitro

2014 ◽  
Vol 82 (8) ◽  
pp. 3324-3332 ◽  
Author(s):  
Lindy M. Fine ◽  
Daniel P. Miller ◽  
Katherine L. Mallory ◽  
Brittney K. Tegels ◽  
Christopher G. Earnhart ◽  
...  
Keyword(s):  
Genetic Manipulation ◽  
Binding Protein ◽  
Factor H ◽  
Negative Regulator ◽  
Human Complement ◽  
Relapsing Fever ◽  
Borrelia Hermsii ◽  
Content Type

ABSTRACTThe primary causative agent of tick-borne relapsing fever in North America isBorrelia hermsii. It has been hypothesized thatB. hermsiievades complement-mediated destruction by binding factor H (FH), a host-derived negative regulator of complement.In vitro,B. hermsiiproduces a single FH binding protein designated FhbA (FH binding protein A). The properties and ligand binding activity of FhbA suggest that it plays multiple roles in pathogenesis. It binds plasminogen and has been identified as a significant target of a B1b B cell-mediated IgM response in mice. FhbA has also been explored as a potential diagnostic antigen forB. hermsiiinfection in humans. The ability to test the hypothesis that FhbA is a critical virulence factorin vivohas been hampered by the lack of well-developed systems for the genetic manipulation of the relapsing fever spirochetes. In this report, we have successfully generated aB. hermsiifhbAdeletion mutant (theB. hermsiiYORΔfhbAstrain) through allelic exchange mutagenesis. Deletion offhbAabolished FH binding by the YORΔfhbAstrain and eliminated cleavage of C3b on the cell surface. However, the YORΔfhbAstrain remained infectious in mice and retained resistance to killingin vitroby human complement. Collectively, these results indicate thatB. hermsiiemploys an FhbA/FH-independent mechanism of complement evasion that allows for resistance to killing by human complement and persistence in mice.

scholarly journals Loa loa Microfilariae Evade Complement Attack In Vivo by Acquiring Regulatory Proteins from Host Plasma

2009 ◽  
Vol 77 (9) ◽  
pp. 3886-3893 ◽  
Author(s):  
Karita Haapasalo ◽  
Taru Meri ◽  
T. Sakari Jokiranta
Keyword(s):  
Complement Activation ◽  
Blood Circulation ◽  
Binding Protein ◽  
Factor H ◽  
Loa Loa ◽  
Continuous Contact ◽  
Subcutaneous Tissues ◽  
Complement Regulators

ABSTRACT Loa loa is a filarial nematode that infects humans. The adults live in subcutaneous tissues and produce microfilariae that live for several weeks in the blood circulation in order to be transmitted to another person via blood meals of a dipterian vector. As microfilariae live in continuous contact with plasma, it is obvious that they evade the complement system. We studied markers of complement activation and signs of complement regulation on Loa loa microfilariae in vivo. The microfilariae were isolated from anticoagulated blood samples of a Loa loa-infected Caucasian patient. C1q and some mannose-binding lectin but only a limited amount of C3b or C4b fragments and practically no C5 or C5b-9 were present on the microfilariae. The covalently microfilaria-bound C3 and C4 depositions were mainly inactive iC3b, C3c, and iC4b fragments indicating that microfilariae had regulated complement activation in vivo. Also, in vitro deposition of C3b onto the microfilariae upon serum exposure was limited. The patient-isolated microfilariae were found to carry the host complement regulators factor H and C4b-binding protein on the outermost layer, so called sheath. The microfilaria-bound factor H was functionally active. Binding of the complement regulators to the microfilariae was confirmed in vitro using 125I-labeled factor H and C4b-binding protein. In conclusion, our study shows that Loa loa microfilariae block complement activation and acquire the host complement regulators factor H and C4b-binding protein in blood circulation. This is the first time that binding of complement regulators onto nonviral pathogens has been demonstrated to occur in humans in vivo.

scholarly journals Proteomic and Transcriptomic Profiling of Staphylococcus aureus Surface LPXTG-proteins: Correlation with agr Genotypes and Adherence Phenotypes

2012 ◽  
Vol 11 (11) ◽  
pp. 1123-1139 ◽  
Author(s):  
Mathilde Ythier ◽  
Grégory Resch ◽  
Patrice Waridel ◽  
Alexandre Panchaud ◽  
Aurélie Gfeller ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Regulatory Networks ◽  
Time Course ◽  
Methicillin Resistance ◽  
Binding Protein ◽  
Protein A ◽  
Surface Proteins ◽  
Protein Domain ◽  
Accessory Gene

Staphylococcus aureus infections involve numerous adhesins and toxins, which expression depends on complex regulatory networks. Adhesins include a family of surface proteins covalently attached to the peptidoglycan via a conserved LPXTG motif. Here we determined the protein and mRNA expression of LPXTG-proteins of S. aureus Newman in time-course experiments, and their relation to fibrinogen adherence in vitro. Experiments were performed with mutants in the global accessory-gene regulator (agr), surface protein A (Spa), and fibrinogen-binding protein A (ClfA), as well as during growth in iron-rich or iron-poor media. Surface proteins were recovered by trypsin-shaving of live bacteria. Released peptides were analyzed by liquid chromatography coupled to tandem mass-spectrometry. To unambiguously identify peptides unique to LPXTG-proteins, the analytical conditions were refined using a reference library of S. aureus LPXTG-proteins heterogeneously expressed in surrogate Lactococcus lactis. Transcriptomes were determined by microarrays. Sixteen of the 18 LPXTG-proteins present in S. aureus Newman were detected by proteomics. Nine LPXTG-proteins showed a bell-shape agr-like expression that was abrogated in agr-negative mutants including Spa, fibronectin-binding protein A (FnBPA), ClfA, iron-binding IsdA, and IsdB, immunomodulator SasH, functionally uncharacterized SasD, biofilm-related SasG and methicillin resistance-related FmtB. However, only Spa and SasH modified their proteomic and mRNA profiles in parallel in the parent and its agr- mutant, whereas all other LPXTG-proteins modified their proteomic profiles independently of their mRNA. Moreover, ClfA became highly transcribed and active in fibrinogen-adherence tests during late growth (24 h), whereas it remained poorly detected by proteomics. On the other hand, iron-regulated IsdA-B-C increased their protein expression by >10-times in iron-poor conditions. Thus, proteomic, transcriptomic, and adherence-phenotype demonstrated differential profiles in S. aureus. Moreover, trypsin peptide signatures suggested differential protein domain exposures in various environments, which might be relevant for anti-adhesin vaccines. A comprehensive understanding of the S. aureus physiology should integrate all three approaches.

scholarly journals Molecular Characterization of the Interaction of Borrelia parkeri and Borrelia turicatae with Human Complement Regulators

2010 ◽  
Vol 78 (5) ◽  
pp. 2199-2208 ◽  
Author(s):  
Melanie Schott ◽  
Sonja Grosskinsky ◽  
Christiane Brenner ◽  
Peter Kraiczy ◽  
Reinhard Wallich
Keyword(s):  
Binding Capacity ◽  
Functional Characterization ◽  
Ectopic Expression ◽  
Factor H ◽  
Human Complement ◽  
Related Protein ◽  
Relapsing Fever ◽  
Extracellular Matrix Components ◽  
Complement Regulators

ABSTRACT In North America, tick-borne relapsing fever is caused by the species Borrelia hermsii, B. parkeri, and B. turicatae, which are transmitted to humans through the bite of the respective infected tick vectors. Here we describe the identification and functional characterization of a surface lipoprotein of B. parkeri, designated BpcA, that binds the human complement regulators factor H and factor H-related protein 1 and, simultaneously, the host protease plasminogen. In contrast, the homologous B. turicatae protein failed to bind human factor H and factor H-related protein 1 but retained its plasminogen binding capacity. Factor H bound to BpcA maintains its regulatory capacity to control C3b deposition and C3 convertase activity. Ectopic expression of BpcA in a serum-sensitive B. burgdorferi strain protects transformed cells from complement-mediated killing. Furthermore, bound plasminogen/plasmin endows B. parkeri and B. turicatae with the potential to degrade extracellular matrix components. These findings expand our understanding of the putative recent evolutionary separation of Borrelia parkeri and Borrelia turicatae, provide evidence that B. parkeri differs from B. turicatae in its ability to resist complement attack, and may help in understanding the pathological processes underlying tick-borne relapsing fever.

BhCRASP-1 of the relapsing fever spirochete Borrelia hermsii is a factor H- and plasminogen-binding protein

2008 ◽  
Vol 298 ◽  
pp. 272-283 ◽  
Author(s):  
Evelyn Rossmann ◽  
Peter Kraiczy ◽  
Pia Herzberger ◽  
Christine Skerka ◽  
Michael Kirschfink ◽  
...  
Keyword(s):  
Binding Protein ◽  
Factor H ◽  
Relapsing Fever ◽  
Borrelia Hermsii

scholarly journals Complement Factor H Is a Serum-binding Protein for Adrenomedullin, and the Resulting Complex Modulates the Bioactivities of Both Partners

2000 ◽  
Vol 276 (15) ◽  
pp. 12292-12300 ◽  
Author(s):  
Rubén Pı́o ◽  
Alfredo Martı́nez ◽  
Edward J. Unsworth ◽  
Jeffrey A. Kowalak ◽  
José A. Bengoechea ◽  
...  
Keyword(s):  
Binding Protein ◽  
Polyacrylamide Gel Electrophoresis ◽  
Cancer Cell Line ◽  
Factor H ◽  
Complement Factor H ◽  
Regulatory Function ◽  
Complement Factor ◽  
Routine Procedure ◽  
Serum Binding Protein

Adrenomedullin (AM) is an important regulatory peptide involved in both physiological and pathological states. We have previously demonstrated the existence of a specific AM-binding protein (AMBP-1) in human plasma. In the present study, we developed a nonradioactive ligand blotting assay, which, together with high pressure liquid chromatography/SDS-polyacrylamide gel electrophoresis purification techniques, allowed us to isolate AMBP-1 to homogeneity. The purified protein was identified as human complement factor H. We show that AM/factor H interaction interferes with the established methodology for quantification of circulating AM. Our data suggest that this routine procedure does not take into account the AM bound to its binding protein. In addition, we show that factor H affects AMin vitrofunctions. It enhances AM-mediated induction of cAMP in fibroblasts, augments the AM-mediated growth of a cancer cell line, and suppresses the bactericidal capability of AM onEscherichia coli. Reciprocally, AM influences the complement regulatory function of factor H by enhancing the cleavage of C3b via factor I. In summary, we report on a potentially new regulatory mechanism of AM biology, the influence of factor H on radioimmunoassay quantification of AM, and the possible involvement of AM as a regulator of the complement cascade.

scholarly journals The Factor H Binding Protein ofNeisseria meningitidisInteracts with Xenosiderophores in Vitro

Biochemistry ◽  
2012 ◽  
Vol 51 (46) ◽  
pp. 9384-9393 ◽  
Author(s):  
Daniele Veggi ◽  
Maria A. Gentile ◽  
Francesca Cantini ◽  
Paola Lo Surdo ◽  
Vincenzo Nardi-Dei ◽  
...  
Keyword(s):  
Binding Protein ◽  
Factor H

scholarly journals Immunological and Molecular Analyses of the Borrelia hermsii Factor H and Factor H-Like Protein 1 Binding Protein, FhbA: Demonstration of Its Utility as a Diagnostic Marker and Epidemiological Tool for Tick-Borne Relapsing Fever

2006 ◽  
Vol 74 (8) ◽  
pp. 4519-4529 ◽  
Author(s):  
Kelley M. Hovis ◽  
Martin E. Schriefer ◽  
Sonia Bahlani ◽  
Richard T. Marconi
Keyword(s):  
Binding Protein ◽  
Pcr Primers ◽  
Factor H ◽  
Antigenic Structure ◽  
Diagnostic Tools ◽  
Relapsing Fever ◽  
Borrelia Hermsii ◽  
Specific Pcr ◽  
Epidemiological Tool ◽  
Species Specific

ABSTRACT It has been demonstrated that Borrelia hermsii, a causative agent of relapsing fever, produces a factor H (FH) and FH-like protein 1 (FHL-1) binding protein. The binding protein has been designated FhbA. To determine if FH/FHL-1 binding is widespread among B. hermsii isolates, a diverse panel of strains was tested for the FH/FHL-1 binding phenotype and FhbA production. Most isolates (23/24) produced FhbA and bound FH/FHL-1. Potential variation in FhbA among isolates was analyzed by DNA sequence analyses. Two genetically distinct FhbA types, designated fhbA1 and fhbA2, were delineated, and type-specific PCR primers were generated to allow for rapid differentiation. Pulsed-field gel electrophoresis and hybridization analyses demonstrated that all isolates that possess the gene carry it on a 200-kb linear plasmid (lp200), whereas isolates that lack the gene lack lp200 and instead carry an lp170. To determine if FhbA is antigenic during infection and to assess the specificity of the response, recombinant FhbA1 (rFhbA1) and rFhbA2 were screened with serum from infected mice and humans. FhbA was found to be expressed and antigenic and to elicit a potentially type-specific FhbA response. To localize the epitopes of FhbA1 and FhbA2, truncations were generated and screened with infection serum. The epitopes were determined to be conformationally defined. Collectively, these analyses indicate that FH/FHL-1 binding is a widespread virulence mechanism for B. hermsii and provide insight into the genetic and antigenic structure of FhbA. The data also have potential implications for understanding the epidemiology of relapsing fever in North America and can be applied to the future development of species-specific diagnostic tools.

scholarly journals Borrelia burgdorferi Escape Mutants That Survive in the Presence of Antiserum to the OspA Vaccine Are Killed When Complement Is Also Present

1998 ◽  
Vol 66 (6) ◽  
pp. 2540-2546 ◽  
Author(s):  
Mónica Solé ◽  
Carlos Bantar ◽  
Karl Indest ◽  
Yan Gu ◽  
Ramesh Ramamoorthy ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Protein A ◽  
Surface Protein ◽  
Sensu Stricto ◽  
Antibody Concentration ◽  
Initial Attempt ◽  
Outer Surface Protein A ◽  
Escape Mutants ◽  
Low Passage

ABSTRACT As an initial attempt to investigate the possible role of outer surface protein A (OspA) escape mutants of Borrelia burgdorferi in decreasing the efficacy of the OspA vaccine, mutants of the HB19 strain of B. burgdorferi sensu stricto were selected in vitro from an uncloned, low-passage-number isolate. The antiserum used for selection was obtained from rhesus monkeys that had been given a vaccine of the same formulation and dose, and by the same route of administration, as that given to humans in several trials. All of the mutants selected in liquid medium and subsequently cloned twice in solid medium expressed a single abundant protein of 28 to 34 kDa instead of both OspA and OspB. Depending on the mutant, this protein reacted strongly, weakly, or not detectably with the anti-OspA antibody used for selection. Analysis of the ospAB locus of each of four representatives from these three groups of mutants by PCR with oligonucleotide primers that hybridize to flanking regions of theospAB operon, and of the corresponding phenotype with monoclonal antibodies that bind to the amino or carboxyl terminus of the OspA or OspB polypeptide, indicated that in all cases a deletion within the operon had occurred. Spirochetes from the four mutant strains chosen for further analysis could be killed in antibody-dependent, complement-mediated killing assays with the selecting anti-OspA antibody, despite their resistance to killing with this antibody in the absence of complement. Complement-mediated killing occurred at an antibody concentration higher than that required to kill wild-type spirochetes. If anti-OspA antibody acts only within the tick, where complement is probably ineffective due to tick-derived decomplementing factors, then OspA escape mutants, if infectious, could seriously diminish the efficacy of OspA vaccines. On the other hand, if the killing of B. burgdorferi with anti-OspA antibody also takes place within the human host, then our results indicate that chimeric/deletion escape mutants will be killed as well.

scholarly journals Active and Passive Immunity against Borrelia burgdorferi Decorin Binding Protein A (DbpA) Protects against Infection

1998 ◽  
Vol 66 (5) ◽  
pp. 2143-2153 ◽  
Author(s):  
Mark S. Hanson ◽  
David R. Cassatt ◽  
Betty P. Guo ◽  
Nita K. Patel ◽  
Michael P. McCarthy ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Low Dose ◽  
Early Stage ◽  
Protein A ◽  
Sensu Stricto ◽  
Passive Immunity ◽  
In Vitro Growth

ABSTRACT Borrelia burgdorferi, the spirochete that causes Lyme disease, binds decorin, a collagen-associated extracellular matrix proteoglycan found in the skin (the site of entry for the spirochete) and in many other tissues. Two borrelial adhesins that recognize this proteoglycan, decorin binding proteins A and B (DbpA and DbpB, respectively), have recently been identified. Infection of mice by low-dose B. burgdorferi challenge elicited antibodies against DbpA and DbpB that were sustained at high levels, suggesting that these antigens are expressed in vivo. Scanning immunoelectron microscopy showed that DbpA was surface accessible on intact borreliae. Passive administration of DbpA antiserum protected mice from infection following challenge with heterologous B. burgdorferi sensu stricto isolates, even when serum administration was delayed for up to 4 days after challenge. DbpA is the first antigen target identified that is capable of mediating immune resolution of early, localizedB. burgdorferi infections. DbpA immunization also protected mice from B. burgdorferi challenge; DbpB immunization was much less effective. DbpA antiserum inhibited in vitro growth of manyB. burgdorferi sensu lato isolates of diverse geographic, phylogenetic, and clinical origins. In combination, these findings support a role for DbpA in the immunoprophylaxis of Lyme disease and suggest that DbpA vaccines have the potential to eliminate early-stageB. burgdorferi infections.

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