Competitive Advantage of Borrelia burgdorferi with Outer Surface Protein BBA03 during Tick-Mediated Infection of the Mammalian Host

ABSTRACTLinear plasmid lp54 is one of the most highly conserved and differentially expressed elements of the segmented genome of the Lyme disease spirocheteBorrelia burgdorferi. We previously reported that deletion of a 4.1-kb region of lp54 (bba01tobba07[bba01-bba07]) led to a slight attenuation of tick-transmitted infection in mice following challenge with a large number of infected ticks. In the current study, we reduced the number of ticks in the challenge to more closely mimic the natural dose and found a profound defect in tick-transmitted infection of thebba01-bba07mutant relative to wild-typeB. burgdorferi. We next focused on deletion ofbba03as the most likely cause of this mutant phenotype, as previous studies have shown that expression ofbba03is increased by culture conditions that simulate tick feeding. Consistent with this hypothesis, we demonstrated increased expression ofbba03by spirochetes in fed relative to unfed ticks. We also observed that abba03deletion mutant, although fully competent by itself, did not efficiently infect mice when transmitted by ticks that were simultaneously coinfected with wild-typeB. burgdorferi. These results suggest that BBA03 provides a competitive advantage to spirochetes carrying this protein during tick transmission to a mammalian host in the natural infectious cycle.

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OspC-Independent Infection and Dissemination by Host-Adapted Borrelia burgdorferi

Infection and Immunity ◽

10.1128/iai.01193-08 ◽

2009 ◽

Vol 77 (7) ◽

pp. 2672-2682 ◽

Cited By ~ 25

Author(s):

Kit Tilly ◽

Aaron Bestor ◽

Daniel P. Dulebohn ◽

Patricia A. Rosa

Keyword(s):

Borrelia Burgdorferi ◽

Mouse Skin ◽

Surface Protein ◽

Mammalian Host ◽

Recipient Mouse ◽

Wild Type ◽

Surface Protein Gene ◽

Tick Transmission ◽

Mammalian Infection

ABSTRACTBorrelia burgdorferiOspC is required for the spirochete to establish infection in a mammal by tick transmission or needle inoculation. After a brief essential period, the protein no longer is required and the gene can be shut off. Using a system in which spirochetes contain only an unstable wild-type copy of theospCgene, we can obtain mice persistently infected with bacteria lacking OspC. We implanted pieces of infected mouse skin subcutaneously in naïve mice, using donors carrying wild-type orospCmutant spirochetes, and found that both could infect mice by this method, with similar numbers of wild-type orospCmutant spirochetes disseminated throughout the tissues of recipient mice. Recipient mouse immune responses to tissue transfer-mediated infection with wild-type orospCmutant spirochetes were similar. These experiments demonstrate that mammalian host-adapted spirochetes can infect and disseminate in mice in the absence of OspC, thereby circumventing this hallmark of tick-derived or in vitro-grown spirochetes. We propose a model in which OspC is one of a succession of functionally equivalent, essential proteins that are synthesized at different stages of mammalian infection. In this model, another protein uniquely present on host-adapted spirochetes performs the same essential function initially fulfilled by OspC. The strict temporal control ofB. burgdorferiouter surface protein gene expression may reflect immunological constraints rather than distinct functions.

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Borrelia burgdorferi bba74 Is Expressed Exclusively during Tick Feeding and Is Regulated by Both Arthropod- and Mammalian Host-Specific Signals

Journal of Bacteriology ◽

10.1128/jb.01802-08 ◽

2009 ◽

Vol 191 (8) ◽

pp. 2783-2794 ◽

Cited By ~ 42

Author(s):

Vishwaroop B. Mulay ◽

Melissa J. Caimano ◽

Radha Iyer ◽

Star Dunham-Ems ◽

Dionysios Liveris ◽

...

Keyword(s):

Borrelia Burgdorferi ◽

Elevated Temperatures ◽

Temperature Shift ◽

Mammalian Host ◽

Wild Type ◽

Tick Feeding ◽

Reciprocal Regulation ◽

Heterogeneous Expression ◽

Membrane Spanning

ABSTRACT Although BBA74 initially was described as a 28-kDa virulence-associated outer-membrane-spanning protein with porin-like function, subsequent studies revealed that it is periplasmic and downregulated in mammalian host-adapted spirochetes. To further elucidate the role of this protein in the Borrelia burgdorferi tick-mammal cycle, we conducted a thorough examination of its expression profile in comparison with the profiles of three well-characterized, differentially expressed borrelial genes (ospA, ospC, and ospE) and their proteins. In vitro, transcripts for bba74 were expressed at 23°C and further enhanced by a temperature shift (37°C), whereas BBA74 protein diminished at elevated temperatures; in contrast, neither transcript nor protein was expressed by spirochetes grown in dialysis membrane chambers (DMCs). Primer extension of wild-type B. burgdorferi grown in vitro, in conjunction with expression analysis of DMC-cultivated wild-type and rpoS mutant spirochetes, revealed that, like ospA, bba74 is transcribed by σ70 and is subject to RpoS-mediated repression within the mammalian host. A series of experiments utilizing wild-type and rpoS mutant spirochetes was conducted to determine the transcriptional and translational profiles of bba74 during the tick-mouse cycle. Results from these studies revealed (i) that bba74 is transcribed by σ70 exclusively during the larval and nymphal blood meals and (ii) that transcription of bba74 is bracketed by RpoS-independent and -dependent forms of repression that are induced by arthropod- and mammalian host-specific signals, respectively. Although loss of BBA74 does not impair the ability of B. burgdorferi to complete its infectious life cycle, the temporal compartmentalization of this gene's transcription suggests that BBA74 facilitates fitness of the spirochete within a narrow window of its tick phase. A reexamination of the paradigm for reciprocal regulation of ospA and ospC, performed herein, revealed that the heterogeneous expression of OspA and OspC displayed by spirochete populations during the nymphal blood meal results from the intricate sequence of transcriptional and translational changes that ensue as B. burgdorferi transitions between its arthropod vector and mammalian host.

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Efficacy of an Experimental Azithromycin Cream for Prophylaxis of Tick-Transmitted Lyme Disease Spirochete Infection in a Murine Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01932-13 ◽

2013 ◽

Vol 58 (1) ◽

pp. 348-351 ◽

Cited By ~ 8

Author(s):

Joseph Piesman ◽

Andrias Hojgaard ◽

Amy J. Ullmann ◽

Marc C. Dolan

Keyword(s):

Lyme Disease ◽

Borrelia Burgdorferi ◽

Murine Model ◽

Systemic Effect ◽

Tick Bite ◽

Single Application ◽

Transmitted Infection ◽

Content Type ◽

Tick Transmission ◽

A Site

ABSTRACTAs an alternative to oral prophylaxis for the prevention of tick transmission ofBorrelia burgdorferi, we tested antibiotic cream prophylactic formulations in a murine model of spirochete infection. A 4% preparation of doxycycline cream afforded no protection, but a single application of 4% azithromycin cream was 100% protective when applied directly to the tick bite site at the time of tick removal. Indeed, the azithromycin cream was 100% effective when applied at up to 3 days after tick removal and protected 74% of mice exposed to tick bite when applied at up to 2 weeks after tick removal. Azithromycin cream was also protective when applied at a site distal to the tick bite site, suggesting that it was having a systemic effect in addition to a local transdermal effect. Mice that were protected from tick-transmitted infection did not seroconvert and did not infect larval ticks on xenodiagnosis. Azithromycin cream formulations appear to hold promise for Lyme disease prophylaxis.

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The BB0345 Hypothetical Protein of Borrelia burgdorferi Is Essential for Mammalian Infection

Infection and Immunity ◽

10.1128/iai.00472-20 ◽

2020 ◽

Vol 88 (12) ◽

Author(s):

Danielle E. Graham ◽

Ashley M. Groshong ◽

Clay D. Jackson-Litteken ◽

Brendan P. Moore ◽

Melissa J. Caimano ◽

...

Keyword(s):

Borrelia Burgdorferi ◽

Transcriptional Regulator ◽

Hypothetical Protein ◽

Proteinase K ◽

Mammalian Host ◽

Wild Type ◽

Content Type ◽

Cell Partitioning ◽

Immunocompetent Mice

ABSTRACT During the natural enzootic life cycle of Borrelia burgdorferi (also known as Borreliella burgdorferi), the bacteria must sense conditions within the vertebrate and arthropod and appropriately regulate expression of genes necessary to persist within these distinct environments. bb0345 of B. burgdorferi encodes a hypothetical protein of unknown function that is predicted to contain an N-terminal helix-turn-helix (HTH) domain. Because HTH domains can mediate protein-DNA interactions, we hypothesized that BB0345 might represent a previously unidentified borrelial transcriptional regulator with the ability to regulate events critical for the B. burgdorferi enzootic cycle. To study the role of BB0345 within mammals, we generated a bb0345 mutant and assessed its virulence potential in immunocompetent mice. The bb0345 mutant was able to initiate localized infection and disseminate to distal tissues but was cleared from all sites by 14 days postinfection. In vitro growth curve analyses revealed that the bb0345 mutant grew similar to wild-type bacteria in standard Barbour-Stoenner-Kelley II (BSK-II) medium; however, the mutant was not able to grow in dilute BSK-II medium or dialysis membrane chambers (DMCs) implanted in rats. Proteinase K accessibility assays and whole-cell partitioning indicated that BB0345 was intracellular and partially membrane associated. Comparison of protein production profiles between the wild-type parent and the bb0345 mutant revealed no major differences, suggesting BB0345 may not be a global transcriptional regulator. Taken together, these data show that BB0345 is essential for B. burgdorferi survival in the mammalian host, potentially by aiding the spirochete with a physiological function that is required by the bacterium during infection.

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An OspC-Specific Monoclonal Antibody Passively Protects Mice from Tick-Transmitted Infection by Borrelia burgdorferi B31

Infection and Immunity ◽

10.1128/iai.67.10.5470-5472.1999 ◽

1999 ◽

Vol 67 (10) ◽

pp. 5470-5472 ◽

Cited By ~ 54

Author(s):

M. Lamine Mbow ◽

Robert D. Gilmore ◽

Richard G. Titus

Keyword(s):

Monoclonal Antibody ◽

Borrelia Burgdorferi ◽

Protein C ◽

Passive Immunization ◽

Surface Protein ◽

Challenge Infection ◽

Specific Monoclonal Antibody ◽

Tick Feeding ◽

Transmitted Infection ◽

Outbred Mice

ABSTRACT A murine monoclonal antibody directed against Borrelia burgdorferi B31 outer surface protein C (OspC) antigen was generated by a method whereby borreliae were inoculated into the mouse via the natural transmission mode of tick feeding. Passive immunization with this antibody resulted in protection of C3H/HeJ and outbred mice from a tick-transmitted challenge infection. Immunofluorescence staining of borrelia cells indicated surface exposure of the OspC epitope reactive with the monoclonal antibody.

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Outer Surface Protein OspC Is an Antiphagocytic Factor That Protects Borrelia burgdorferi from Phagocytosis by Macrophages

Infection and Immunity ◽

10.1128/iai.01215-15 ◽

2015 ◽

Vol 83 (12) ◽

pp. 4848-4860 ◽

Cited By ~ 42

Author(s):

Sebastian E. Carrasco ◽

Bryan Troxell ◽

Youyun Yang ◽

Stephanie L. Brandt ◽

Hongxia Li ◽

...

Keyword(s):

Borrelia Burgdorferi ◽

Outer Surface ◽

Fluorescent Protein ◽

Surface Protein ◽

Peritoneal Macrophages ◽

Mononuclear Phagocytes ◽

Tick Feeding ◽

Content Type ◽

Outer Surface Protein ◽

Murine Peritoneal Macrophages

Outer surface protein C (OspC) is one of the major lipoproteins expressed on the surface ofBorrelia burgdorferiduring tick feeding and the early phase of mammalian infection. OspC is required forB. burgdorferito establish infection in both immunocompetent and SCID mice and has been proposed to facilitate evasion of innate immune defenses. However, the exact biological function of OspC remains elusive. In this study, we showed that theospC-deficient spirochete could not establish infection in NOD-scid IL2rγnullmice that lack B cells, T cells, NK cells, and lytic complement. TheospCmutant also could not establish infection in anti-Ly6G-treated SCID and C3H/HeN mice (depletion of neutrophils). However, depletion of mononuclear phagocytes at the skin site of inoculation in SCID and C3H/HeN mice allowed theospCmutant to establish infectionin vivo. In phagocyte-depleted mice, theospCmutant was able to colonize the joints and triggered neutrophilia during dissemination. Furthermore, we found that phagocytosis of green fluorescent protein (GFP)-expressingospCmutant spirochetes by murine peritoneal macrophages and human THP-1 macrophage-like cells, but not in PMN-HL60, was significantly higher than parental wild-typeB. burgdorferistrains, suggesting that OspC has an antiphagocytic property. In addition, overproduction of OspC in spirochetes also decreased the uptake of spirochetes by murine peritoneal macrophages. Together, our findings provide evidence that mononuclear phagocytes play a key role in clearance of theospCmutant and that OspC promotes spirochetes' evasion of macrophages during early Lyme borreliosis.

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Borrelia burgdorferi bba66Gene Inactivation Results in Attenuated Mouse Infection by Tick Transmission

Infection and Immunity ◽

10.1128/iai.00140-13 ◽

2013 ◽

Vol 81 (7) ◽

pp. 2488-2498 ◽

Cited By ~ 20

Author(s):

Toni G. Patton ◽

Kevin S. Brandt ◽

Christi Nolder ◽

Dawn R. Clifton ◽

James A. Carroll ◽

...

Keyword(s):

Borrelia Burgdorferi ◽

Ixodes Scapularis ◽

Disease Process ◽

Mammalian Host ◽

Content Type ◽

Tick Vector ◽

Tick Transmission ◽

Encoding Gene ◽

Host Infection ◽

The Impact

ABSTRACTThe impact of theBorrelia burgdorferisurface-localized immunogenic lipoprotein BBA66 on vector and host infection was evaluated by inactivating the encoding gene,bba66, and characterizing the mutant phenotype throughout the natural mouse-tick-mouse cycle. The BBA66-deficient mutant isolate, BbΔA66, remained infectious in mice by needle inoculation of cultured organisms, but differences in spirochete burden and pathology in the tibiotarsal joint were observed relative to the parental wild-type (WT) strain.Ixodes scapularislarvae successfully acquired BbΔA66following feeding on infected mice, and the organisms persisted in these ticks through the molt to nymphs. A series of tick transmission experiments (n= 7) demonstrated that the ability of BbΔA66-infected nymphs to infect laboratory mice was significantly impaired compared to that of mice fed upon by WT-infected ticks.trans-complementation of BbΔA66with an intact copy ofbba66restored the WT infectious phenotype in mice via tick transmission. These results suggest a role for BBA66 in facilitatingB. burgdorferidissemination and transmission from the tick vector to the mammalian host as part of the disease process for Lyme borreliosis.

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Role of the Surface Lipoprotein BBA07 in the Enzootic Cycle of Borrelia burgdorferi

Infection and Immunity ◽

10.1128/iai.00372-10 ◽

2010 ◽

Vol 78 (7) ◽

pp. 2910-2918 ◽

Cited By ~ 28

Author(s):

Haijun Xu ◽

Ming He ◽

Jane Jingyuan He ◽

X. Frank Yang

Keyword(s):

Borrelia Burgdorferi ◽

Protein Profile ◽

Mammalian Host ◽

Tick Feeding ◽

Tick Transmission ◽

Nymphal Tick ◽

Encoding Gene ◽

Enzootic Cycle

ABSTRACT Borrelia burgdorferi, the Lyme disease pathogen, dramatically alters its protein profile when it is transmitted between ticks and mammals. Several differentially expressed proteins have been shown to be critical for the enzootic cycle of B. burgdorferi. In this study, we demonstrated that expression of the surface lipoprotein-encoding gene bba07 is induced by an elevated temperature and a reduced pH during in vitro cultivation, as well as during nymphal tick feeding. Expression of bba07 is regulated by the Rrp2-RpoN-RpoS pathway, a central regulatory network that is activated during nymphal feeding. By generating a bba07 mutant of an infectious strain of B. burgdorferi, we demonstrated that although BBA07-deficient spirochetes were capable of infecting mice via needle inoculation and surviving in ticks, they were defective in infection of mammals via tick transmission. Complementation of the bba07 mutant with a wild-type copy of bba07 partially restored the transmission defect of the bba07 mutant. Based on these findings, we concluded that the surface lipoprotein BBA07 is produced during tick feeding and facilitates optimal transmission of B. burgdorferi from the tick vector to a mammalian host.

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Borrelia burgdorferi Lacking BBK32, a Fibronectin-Binding Protein, Retains Full Pathogenicity

Infection and Immunity ◽

10.1128/iai.02035-05 ◽

2006 ◽

Vol 74 (6) ◽

pp. 3305-3313 ◽

Cited By ~ 68

Author(s):

Xin Li ◽

Xianzhong Liu ◽

Deborah S. Beck ◽

Fred S. Kantor ◽

Erol Fikrig

Keyword(s):

Life Cycle ◽

Borrelia Burgdorferi ◽

Deletion Mutant ◽

Binding Protein ◽

Kanamycin Resistance ◽

Binding Activity ◽

Mammalian Host ◽

Wild Type ◽

Fibronectin Binding Protein ◽

Fibronectin Binding

ABSTRACT BBK32, a fibronectin-binding protein of Borrelia burgdorferi, is one of many surface lipoproteins that are differentially expressed by the Lyme disease spirochete at various stages of its life cycle. The level of BBK32 expression in B. burgdorferi is highest during infection of the mammalian host and lowest in flat ticks. This temporal expression profile, along with its fibronectin-binding activity, strongly suggests that BBK32 may play an important role in Lyme pathogenesis in the host. To test this hypothesis, we constructed an isogenic BBK32 deletion mutant from wild-type B. burgdorferi B31 by replacing the BBK32 gene with a kanamycin resistance cassette through homologous recombination. We examined both the wild-type strain and the BBK32 deletion mutant extensively in the experimental mouse-tick model of the Borrelia life cycle. Our data indicated that B. burgdorferi lacking BBK32 retained full pathogenicity in mice, regardless of whether mice were infected artificially by syringe inoculation or naturally by tick bite. The loss of BBK32 expression in the mutant had no adverse effect on spirochete acquisition (mouse-to-tick) and transmission (tick-to-mouse) processes. These results suggest that additional B. burgdorferi proteins can complement the function of BBK32, fibronectin binding or otherwise, during the natural spirochete life cycle.

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The luxS Gene Is Not Required for Borrelia burgdorferi Tick Colonization, Transmission to a Mammalian Host, or Induction of Disease

Infection and Immunity ◽

10.1128/iai.72.8.4864-4867.2004 ◽

2004 ◽

Vol 72 (8) ◽

pp. 4864-4867 ◽

Cited By ~ 23

Author(s):

Jon S. Blevins ◽

Andrew T. Revel ◽

Melissa J. Caimano ◽

Xiaofeng F. Yang ◽

James A. Richardson ◽

...

Keyword(s):

Borrelia Burgdorferi ◽

Ixodes Scapularis ◽

Mammalian Host ◽

Luxs Gene ◽

Wild Type ◽

Molting Process

ABSTRACT luxS mutants of Borrelia burgdorferi strain 297 naturally colonized their arthropod (Ixodes scapularis) vector, were maintained in ticks throughout the molting process (larvae to nymphs), were tick transmitted to uninfected mice, and elicited histopathology in mice indistinguishable from that induced by wild-type B. burgdorferi.

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