scholarly journals Borrelia burgdorferi RevA Significantly Affects Pathogenicity and Host Response in the Mouse Model of Lyme Disease

2015 ◽  
Vol 83 (9) ◽  
pp. 3675-3683 ◽  
Author(s):  
Rebecca Byram ◽  
Robert A. Gaultney ◽  
Angela M. Floden ◽  
Christopher Hellekson ◽  
Brandee L. Stone ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Host Response ◽  
Collagen Deposition ◽  
Wild Type ◽  
Content Type ◽  
Cardiac Tissues ◽  
Monocyte Chemoattractant ◽  
Bacterial Interaction ◽  
Mammalian Infection

The Lyme disease spirochete,Borrelia burgdorferi, expresses RevA and numerous outer surface lipoproteins during mammalian infection. As an adhesin that promotes bacterial interaction with fibronectin, RevA is poised to interact with the extracellular matrix of the host. To further define the role(s) of RevA during mammalian infection, we created a mutant that is unable to produce RevA. The mutant was still infectious to mice, although it was significantly less well able to infect cardiac tissues. Complementation of the mutant with a wild-typerevAgene restored heart infectivity to wild-type levels. Additionally,revAmutants led to increased evidence of arthritis, with increased fibrotic collagen deposition in tibiotarsal joints. The mutants also induced increased levels of the chemokine CCL2, a monocyte chemoattractant, in serum, and this increase was abolished in the complemented strain. Therefore, whilerevAis not absolutely essential for infection, deletion ofrevAhad distinct effects on dissemination, arthritis severity, and host response.

scholarly journals Evaluation of RevA, a Fibronectin-Binding Protein of Borrelia burgdorferi, as a Potential Vaccine Candidate for Lyme Disease

2013 ◽  
Vol 20 (6) ◽  
pp. 892-899 ◽  
Author(s):  
Angela M. Floden ◽  
Tammy Gonzalez ◽  
Robert A. Gaultney ◽  
Catherine A. Brissette
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Passive Immunization ◽  
Surface Protein ◽  
Surface Expression ◽  
Content Type ◽  
Good Target ◽  
Potential Vaccine ◽  
Mammalian Infection

ABSTRACTPrevious studies indicated that the Lyme disease spirocheteBorrelia burgdorferiexpresses the RevA outer surface protein during mammalian infection. As an adhesin that promotes bacterial interaction with fibronectin, RevA appears to be a good target for preventive therapies. RevA proteins are highly conserved across all Lyme borreliae, and antibodies against RevA protein are cross-reactive among RevA proteins from diverse strains. Mice infected withB. burgdorferimounted a rapid IgM response to RevA, followed by a strong IgG response that generally remained elevated for more than 12 months, suggesting continued exposure of RevA protein to the immune system. RevA antibodies were bactericidalin vitro. To evaluate the RevA antigen as a potential vaccine, mice were vaccinated with recombinant RevA and challenged withB. burgdorferiby inoculation with a needle or by a tick bite. Cultured tissues from all treatment groups were positive forB. burgdorferi. Vaccinated animals also appeared to have similar levels ofB. burgdorferiDNA compared to nonvaccinated controls. Despite its antigenicity, surface expression, and the production of bactericidal antibodies against it, RevA does not protect againstBorrelia burgdorferiinfection in a mouse model. However, passive immunization with anti-RevA antibodies did prevent infection, suggesting the possible utility of RevA-based immunotherapeutics or vaccine.

scholarly journals Apparent Role for Borrelia burgdorferi LuxS during Mammalian Infection

2015 ◽  
Vol 83 (4) ◽  
pp. 1347-1353 ◽  
Author(s):  
William K. Arnold ◽  
Christina R. Savage ◽  
Alyssa D. Antonicello ◽  
Brian Stevenson
Keyword(s):  
Borrelia Burgdorferi ◽  
Expression Patterns ◽  
The Other ◽  
Infection Cycle ◽  
Wild Type ◽  
Content Type ◽  
Significant Function ◽  
Autoinducer 2 ◽  
Associated Proteins ◽  
Mammalian Infection

The Lyme disease spirochete,Borrelia burgdorferi, controls protein expression patterns during its tick-mammal infection cycle. Earlier studies demonstrated thatB. burgdorferisynthesizes 4,5-dihydroxy-2,3-pentanedione (autoinducer-2 [AI-2]) and responds to AI-2 by measurably changing production of several infection-associated proteins.luxSmutants, which are unable to produce AI-2, exhibit altered production of several proteins.B. burgdorfericannot utilize the other product of LuxS, homocysteine, indicating that phenotypes ofluxSmutants are not due to the absence of that molecule. Although a previous study found that aluxSmutant was capable of infecting mice, a critical caveat to those results is that bacterial loads were not quantified. To more precisely determine whether LuxS serves a role in mammalian infection, mice were simultaneously inoculated with congenic wild-type andluxSstrains, and bacterial numbers were assessed using quantitative PCR. The wild-type bacteria substantially outcompeted the mutants, suggesting that LuxS performs a significant function during mammalian infection. These data also provide further evidence that nonquantitative infection studies do not necessarily provide conclusive results and that regulatory factors may not make all-or-none, black-or-white contributions to infectivity.

scholarly journals Borrelia burgdorferi Binding of Host Complement Regulator Factor H Is Not Required for Efficient Mammalian Infection

2007 ◽  
Vol 75 (6) ◽  
pp. 3131-3139 ◽  
Author(s):  
Michael E. Woodman ◽  
Anne E. Cooley ◽  
Jennifer C. Miller ◽  
John J. Lazarus ◽  
Kathryn Tucker ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Alternative Pathway ◽  
Host Factor ◽  
Factor H ◽  
Surface Proteins ◽  
Wild Type ◽  
Factor B ◽  
Mammalian Infection ◽  
Deficient Mice

ABSTRACT The causative agent of Lyme disease, Borrelia burgdorferi, is naturally resistant to its host's alternative pathway of complement-mediated killing. Several different borrelial outer surface proteins have been identified as being able to bind host factor H, a regulator of the alternative pathway, leading to a hypothesis that such binding is important for borrelial resistance to complement. To test this hypothesis, the development of B. burgdorferi infection was compared between factor H-deficient and wild-type mice. Factor B- and C3-deficient mice were also studied to determine the relative roles of the alternative and classical/lectin pathways in B. burgdorferi survival during mammalian infection. While it was predicted that B. burgdorferi should be impaired in its ability to infect factor H-deficient animals, quantitative analyses of bacterial loads indicated that those mice were infected at levels similar to those of wild-type and factor B- and C3-deficient mice. Ticks fed on infected factor H-deficient or wild-type mice all acquired similar numbers of bacteria. Indirect immunofluorescence analysis of B. burgdorferi acquired by feeding ticks from the blood of infected mice indicated that none of the bacteria had detectable levels of factor H on their outer surfaces, even though such bacteria express high levels of surface proteins capable of binding factor H. These findings demonstrate that the acquisition of host factor H is not essential for mammalian infection by B. burgdorferi and indicate that additional mechanisms are employed by the Lyme disease spirochete to evade complement-mediated killing.

scholarly journals Enhanced Detection of Host Response Antibodies to Borrelia burgdorferi Using Immuno-PCR

2013 ◽  
Vol 20 (3) ◽  
pp. 350-357 ◽  
Author(s):  
Micah D. Halpern ◽  
Sunny Jain ◽  
Mollie W. Jewett
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Host Response ◽  
Magnetic Beads ◽  
Disease Patient ◽  
Rank Correlation ◽  
Protein Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Content Type

ABSTRACTLyme disease is the fastest-growing zoonotic disease in North America. Current methods for detection ofBorrelia burgdorferiinfection are challenged by analysis subjectivity and standardization of antigen source. In the present study, we developed an immuno-PCR (iPCR)-based approach employing recombinantin vivo-expressedB. burgdorferiantigens for objective detection of a host immune response toB. burgdorferiinfection. iPCR is a liquid-phase protein detection method that combines the sensitivity of PCR with the specificity and versatility of immunoassay-based protocols. Use of magnetic beads coated with intact spirochetes provided effective antigen presentation and allowed detection of host-generated antibodies in experimentally infected mice at day 11 postinoculation, whereas host-generated antibodies were detected at day 14 by enzyme-linked immunosorbent assay (ELISA) and day 21 by immunoblotting. Furthermore, magnetic beads coated with recombinantB. burgdorferi in vivo-expressed antigen OspC or BmpA demonstrated positive detection of host-generated antibodies in mice at day 7 postinoculation with markedly increased iPCR signals above the background, with the quantification cycle (Cq) value for each sample minus the mean backgroundCqplus 3 standard deviations (ΔCq) being 4 to 10, whereas ΔCqwas 2.5 for intact spirochete-coated beads. iPCR demonstrated a strong correlation (Spearman rank correlation = 0.895,P< 0.0001) with a commercial ELISA for detection of host antibodies in human Lyme disease patient sera using theB. burgdorferiVlsE C6 peptide. In addition, iPCR showed potential applicability for direct detection of spirochetes in blood. The results presented here indicate that our iPCR assay has the potential to provide an objective format that can be used for sensitive detection of multiple host response antibodies and isotypes toB. burgdorferiinfection.

scholarly journals DksA Controls the Response of the Lyme Disease SpirocheteBorrelia burgdorferito Starvation

2018 ◽  
Vol 201 (4) ◽  
Author(s):  
William K. Boyle ◽  
Ashley M. Groshong ◽  
Dan Drecktrah ◽  
Julie A. Boylan ◽  
Frank C. Gherardini ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Regulatory Protein ◽  
Stringent Response ◽  
Differentially Expressed ◽  
Complete Medium ◽  
Wild Type ◽  
Transcriptional Responses ◽  
Content Type ◽  
Vertebrate Hosts

ABSTRACTThe pathogenic spirocheteBorrelia burgdorferisenses and responds to changes in the environment, including changes in nutrient availability, throughout its enzootic cycle inIxodesticks and vertebrate hosts. This study examined the role of DnaK suppressor protein (DksA) in the transcriptional response ofB. burgdorferito starvation. Wild-type anddksAmutantB. burgdorferistrains were subjected to starvation by shifting cultures grown in rich complete medium, Barbour-Stoenner-Kelly II (BSK II) medium, to a defined mammalian tissue culture medium, RPMI 1640, for 6 h under microaerobic conditions (5% CO2, 3% O2). Microarray analyses of wild-typeB. burgdorferirevealed that genes encoding flagellar components, ribosomal proteins, and DNA replication machinery were downregulated in response to starvation. DksA mediated transcriptomic responses to starvation inB. burgdorferi, as thedksA-deficient strain differentially expressed only 47 genes in response to starvation compared to the 500 genes differentially expressed in wild-type strains. Consistent with a role for DksA in the starvation response ofB. burgdorferi, fewer CFU ofdksAmutants were observed after prolonged starvation in RPMI 1640 medium than CFU of wild-typeB. burgdorferispirochetes. Transcriptomic analyses revealed a partial overlap between the DksA regulon and the regulon of RelBbu, the guanosine tetraphosphate and guanosine pentaphosphate [(p)ppGpp] synthetase that controls the stringent response; the DksA regulon also included many plasmid-borne genes. Additionally, thedksAmutant exhibited constitutively elevated (p)ppGpp levels compared to those of the wild-type strain, implying a regulatory relationship between DksA and (p)ppGpp. Together, these data indicate that DksA, along with (p)ppGpp, directs the stringent response to effectB. burgdorferiadaptation to its environment.IMPORTANCEThe Lyme disease bacteriumBorrelia burgdorferisurvives diverse environmental challenges as it cycles between its tick vectors and various vertebrate hosts.B. burgdorferimust withstand prolonged periods of starvation while it resides in unfedIxodesticks. In this study, the regulatory protein DksA is shown to play a pivotal role controlling the transcriptional responses ofB. burgdorferito starvation. The results suggest that DksA gene regulatory activity impactsB. burgdorferimetabolism, virulence gene expression, and the ability of this bacterium to complete its natural life cycle.

scholarly journals Manganese and Zinc Regulate Virulence Determinants in Borrelia burgdorferi

2013 ◽  
Vol 81 (8) ◽  
pp. 2743-2752 ◽  
Author(s):  
Bryan Troxell ◽  
Meiping Ye ◽  
Youyun Yang ◽  
Sebastian E. Carrasco ◽  
Yongliang Lou ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Critical Role ◽  
Transition Metal Ions ◽  
Mammalian Host ◽  
Virulence Determinants ◽  
Temperature Dependent ◽  
Content Type ◽  
Mammalian Infection

ABSTRACTBorrelia burgdorferi, the causative agent of Lyme disease, must adapt to two diverse niches, an arthropod vector and a mammalian host. RpoS, an alternative sigma factor, plays a central role in spirochetal adaptation to the mammalian host by governing expression of many genes important for mammalian infection.B. burgdorferiis known to be unique in metal utilization, and little is known of the role of biologically available metals inB. burgdorferi. Here, we identified two transition metal ions, manganese (Mn2+) and zinc (Zn2+), that influenced regulation of RpoS. The intracellular Mn2+level fluctuated approximately 20-fold under different conditions and inversely correlated with levels of RpoS and the major virulence factor OspC. Furthermore, an increase in intracellular Mn2+repressed temperature-dependent induction of RpoS and OspC; this repression was overcome by an excess of Zn2+. Conversely, a decrease of intracellular Mn2+by deletion of the Mn2+transporter gene,bmtA, resulted in elevated levels of RpoS and OspC. Mn2+affected RpoS through BosR, a Fur family homolog that is required forrpoSexpression: elevated intracellular Mn2+levels greatly reduced the level of BosR protein but not the level ofbosRmRNA. Thus, Mn2+and Zn2+appeared to be important in modulation of the RpoS pathway that is essential to the life cycle of the Lyme disease spirochete. This finding supports the emerging notion that transition metals such as Mn2+and Zn2+play a critical role in regulation of virulence in bacteria.

scholarly journals Live Attenuated Borrelia burgdorferi Targeted Mutants in an Infectious Strain Background Protect Mice from Challenge Infection

2016 ◽  
Vol 23 (8) ◽  
pp. 725-731 ◽  
Author(s):  
Beth L. Hahn ◽  
Lavinia J. Padmore ◽  
Laura C. Ristow ◽  
Michael W. Curtis ◽  
Jenifer Coburn
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Parental Strain ◽  
Content Type ◽  
Protective Antigens ◽  
Homologous Strain ◽  
Live Bacteria ◽  
At Risk Populations ◽  
Mammalian Infection

ABSTRACTBorrelia burgdorferi,B. garinii, andB. afzeliiare all agents of Lyme disease in different geographic locations. If left untreated, Lyme disease can cause significant and long-term morbidity, which may continue after appropriate antibiotic therapy has been administered and live bacteria are no longer detectable. The increasing incidence and geographic spread of Lyme disease are renewing interest in the vaccination of at-risk populations. We took the approach of vaccinating mice with two targeted mutant strains ofB. burgdorferithat, unlike the parental strain, are avirulent in mice. Mice vaccinated with both strains were protected against a challenge with the parental strain and a heterologousB. burgdorferistrain by either needle inoculation or tick bite. In ticks, the homologous strain was eliminated but the heterologous strain was not, suggesting that the vaccines generated a response to antigens that are produced by the bacteria both early in mammalian infection and in the tick. Partial protection againstB. gariniiinfection was also conferred. Protection was antibody mediated, and reactivity to a variety of proteins was observed. These experiments suggest that live attenuatedB. burgdorferistrains may be informative regarding the identification of protective antigens produced by the bacteria and recognized by the mouse immune systemin vivo. Further work may illuminate new candidates that are effective and safe for the development of Lyme disease vaccines.

scholarly journals Effect of Borrelia burgdorferi OspC at the Site of Inoculation in Mouse Skin

2010 ◽  
Vol 78 (11) ◽  
pp. 4723-4733 ◽  
Author(s):  
Styliani Antonara ◽  
Laura Ristow ◽  
James McCarthy ◽  
Jenifer Coburn
Keyword(s):  
Borrelia Burgdorferi ◽  
Mouse Skin ◽  
Vascular Endothelial ◽  
Wild Type ◽  
Monocyte Chemoattractant Protein 1 ◽  
Monocyte Chemoattractant ◽  
Endothelial Growth Factor ◽  
Kinetics Of ◽  
Precise Role

ABSTRACT The Borrelia burgdorferi surface lipoprotein OspC is a critical virulence factor, but its precise role in the establishment of B. burgdorferi infection remains unclear. To determine whether OspC affects the host response at the site of inoculation of the bacterium, the recruitment of macrophages and neutrophils and the production of cytokines were examined at the site of infection by wild-type, ospC mutant, and complemented mutant B. burgdorferi strains. Of the 21 cytokines tested, monocyte chemoattractant protein 1 (MCP-1), keratinocyte-derived chemokine (KC, CXCL1), and vascular endothelial growth factor (VEGF) were found at increased levels at the site of inoculation of B. burgdorferi, and the levels varied with the production of OspC at one or more time points over the 1-week course of infection. The kinetics of expression and the dependence on OspC production by B. burgdorferi varied among the cytokines. The production of KC and MCP-1, and the appearance of monocytic infiltrates, correlated with the presence of the bacteria rather than with OspC specifically. In contrast, VEGF production was not correlated simply to the presence of the bacteria and is influenced by the presence of OspC. In in vitro assays, OspC and B. burgdorferi expressing OspC stimulated the growth of endothelial cells more than did the controls. These data suggest the possibility of a novel role for OspC in the life of B. burgdorferi at the interface of its mammalian and tick hosts.

scholarly journals Borrelia burgdorferi RevA Antigen Binds Host Fibronectin

2009 ◽  
Vol 77 (7) ◽  
pp. 2802-2812 ◽  
Author(s):  
Catherine A. Brissette ◽  
Tomasz Bykowski ◽  
Anne E. Cooley ◽  
Amy Bowman ◽  
Brian Stevenson
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Surface Protein ◽  
Site Directed Mutagenesis ◽  
Heparin Binding ◽  
Amino Terminal ◽  
Ligand Interactions ◽  
Fibronectin Binding Protein ◽  
Vertebrate Hosts ◽  
Mammalian Infection

ABSTRACT Borrelia burgdorferi, the Lyme disease-causing spirochete, can persistently infect its vertebrate hosts for years. B. burgdorferi is often found associated with host connective tissue, where it interacts with components of the extracellular matrix, including fibronectin. Some years ago, a borrelial surface protein, named BBK32, was identified as a fibronectin-binding protein. However, B. burgdorferi BBK32 mutants are still able to bind fibronectin, indicating that the spirochete possesses additional mechanisms for adherence to fibronectin. We now demonstrate that RevA, an unrelated B. burgdorferi outer surface protein, binds mammalian fibronectin in a saturable manner. Site-directed mutagenesis studies identified the amino terminus of the RevA protein as being required for adhesion to fibronectin. RevA bound to the amino-terminal region of fibronectin. RevA binding to fibronectin was not inhibited by salt or heparin, suggesting that adhesin-ligand interactions are primarily nonionic and occur through the non-heparin-binding regions of the fibronectin amino-terminal domains. revA genes are widely distributed among Lyme disease spirochetes, and the present studies determined that all RevA alleles tested bound fibronectin. In addition, RevB, a paralogous protein found in a subset of B. burgdorferi strains, also bound fibronectin. We also confirmed that RevA is produced during mammalian infection but not during colonization of vector ticks and determined that revA transcription is controlled through a mechanism distinct from that of BBK32.

scholarly journals Use of rpsL as a Counterselectable Marker in Borrelia burgdorferi

2009 ◽  
Vol 76 (3) ◽  
pp. 985-987 ◽  
Author(s):  
Dan Drecktrah ◽  
J. Miles Douglas ◽  
D. Scott Samuels
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Causative Agent ◽  
Ribosomal Subunit ◽  
Streptomycin Resistance ◽  
Wild Type ◽  
Small Ribosomal Subunit ◽  
Disease Mutations

ABSTRACT We have demonstrated that rpsL, encoding the S12 protein of the small ribosomal subunit, can be used as a counterselectable marker in Borrelia burgdorferi, the causative agent of Lyme disease. Mutations in rpsL confer streptomycin resistance. Streptomycin susceptibility is dominant in an rpsL merodiploid, and streptomycin selects for the loss of wild-type rpsL carried in trans. This is the first description of a counterselectable marker in B. burgdorferi.

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