1
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Rana VS, Kitsou C, Dumler JS, Pal U. Immune evasion strategies of major tick-transmitted bacterial pathogens. Trends Microbiol 2023; 31:62-75. [PMID: 36055896 PMCID: PMC9772108 DOI: 10.1016/j.tim.2022.08.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/28/2022] [Accepted: 08/01/2022] [Indexed: 12/30/2022]
Abstract
Tick-transmitted bacterial pathogens thrive in enzootic infection cycles, colonizing disparate vertebrate and arthropod tissues, often establishing persistent infections. Therefore, the evolution of robust immune evasion strategies is central to their successful persistence or transmission between hosts. To survive in nature, these pathogens must counteract a broad range of microbicidal host responses that can be localized, tissue-specific, or systemic, including a mix of these responses at the host-vector interface. Herein, we review microbial immune evasion strategies focusing on Lyme disease spirochetes and rickettsial or tularemia agents as models for extracellular and intracellular tick-borne pathogens, respectively. A better understanding of these adaptive strategies could enrich our knowledge of the infection biology of relevant tick-borne diseases, contributing to the development of future preventions.
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Affiliation(s)
- Vipin Singh Rana
- Department of Veterinary Medicine, University of Maryland, College Park, MD, USA
| | - Chrysoula Kitsou
- Department of Veterinary Medicine, University of Maryland, College Park, MD, USA
| | - J Stephen Dumler
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland, College Park, MD, USA.
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2
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Controlled Proteolysis of an Essential Virulence Determinant Dictates Infectivity of Lyme Disease Pathogens. Infect Immun 2022; 90:e0005922. [PMID: 35416705 DOI: 10.1128/iai.00059-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The Borrelia burgdorferi BB0323 protein undergoes a complex yet poorly defined proteolytic maturation event that generates N-terminal and C-terminal proteins with essential functions in cell growth and infection. Here, we report that a borrelial protease, B. burgdorferi high temperature requirement A protease (BbHtrA), cleaves BB0323 between asparagine (N) and leucine (L) at positions 236 and 237, while the replacement of these residues with alanine in the mutant protein prevents its cleavage, despite preserving its normal secondary structure. The N-terminal BB0323 protein binds BbHtrA, but its cleavage site mutant displays deficiency in such interaction. An isogenic borrelial mutant with NL-to-AA substitution in BB0323 (referred to as Bbbb0323NL) maintains normal growth yet is impaired for infection of mice or transmission from infected ticks. Notably, the BB0323 protein is still processed in Bbbb0323NL, albeit with lower levels of mature N-terminal BB0323 protein and multiple aberrantly processed polypeptides, which could result from nonspecific cleavages at other asparagine and leucine residues in the protein. The lack of infectivity of Bbbb0323NL is likely due to the impaired abundance or stoichiometry of a protein complex involving BB0238, another spirochete protein. Together, these studies highlight that a precise proteolytic event and a particular protein-protein interaction, involving multiple borrelial virulence determinants, are mutually inclusive and interconnected, playing essential roles in the infectivity of Lyme disease pathogens.
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3
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Characterization of the Flagellar Collar Reveals Structural Plasticity Essential for Spirochete Motility. mBio 2021; 12:e0249421. [PMID: 34809456 PMCID: PMC8609358 DOI: 10.1128/mbio.02494-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Spirochetes are a remarkable group of bacteria with distinct morphology and periplasmic flagella that enable motility in viscous environments, such as host connective tissues. The collar, a spirochete-specific complex of the periplasmic flagellum, is required for this unique spirochete motility, yet it has not been clear how the collar assembles and enables spirochetes to transit between complex host environments. Here, we characterize the collar complex in the Lyme disease spirochete Borrelia burgdorferi. We discover as well as delineate the distinct functions of two novel collar proteins, FlcB and FlcC, by combining subtractive bioinformatic, genetic, and cryo-electron tomography approaches. Our high-resolution in situ structures reveal that the multiprotein collar has a remarkable structural plasticity essential not only for assembly of flagellar motors in the highly curved membrane of spirochetes but also for generation of the high torque necessary for spirochete motility.
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4
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Klouwens MJ, Trentelman JJ, Ersoz JI, Nieves Marques Porto F, Sima R, Hajdusek O, Thakur M, Pal U, Hovius JW. Investigating BB0405 as a novel Borrelia afzelii vaccination candidate in Lyme borreliosis. Sci Rep 2021; 11:4775. [PMID: 33637813 PMCID: PMC7910573 DOI: 10.1038/s41598-021-84130-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 02/01/2021] [Indexed: 01/20/2023] Open
Abstract
BB0405 is a surface exposed Borrelia burgdorferi protein and its vaccination protected mice against B. burgdorferi infection. As BB0405 is highly conserved across different B. burgdorferi sensu lato species, we investigated whether vaccination with recombinant BB0405 or through intradermal bb0405 DNA tattoo vaccination could provide protection against different Borrelia species, specifically against Borrelia afzelii, the predominant B. burgdorferi sensu lato genospecies causing Lyme borreliosis across Eurasia. We immunized C3H/HeN mice with recombinant BB0405 or with a codon-optimized bb0405 DNA vaccine using the pVAC plasmid and immunized corresponding control groups mice with only adjuvant or empty vectors. We subsequently subjected these immunized mice to a tick challenge with B. afzelii CB43-infected Ixodes ricinus nymphs. Upon vaccination, recombinant BB0405 induced a high total IgG response, but bb0405 DNA vaccination did not elicit antibody responses. Both vaccine formulations did not provide protection against Borrelia afzelii strain CB43 after tick challenge. In an attempt to understand the lack of protection of the recombinant vaccine, we determined expression of BB0405 and showed that B. afzelii CB43 spirochetes significantly and drastically downregulate the expression of BB0405 protein at 37 °C compared to 33 °C, where as in B. burgdorferi B31 spirochetes expression levels remain unaltered. Vaccination with recombinant BB0405 was previously shown to protect against B. burgdorferi sensu stricto. Here we show that vaccination with either recombinant BB0405 (or non-immunogenic bb0405 DNA), despite being highly conserved among B. burgdorferi sl genospecies, does not provide cross-protection against B. afzelii, mostly likely due to downregulation of this protein in B. afzelii in the mammalian host.
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Affiliation(s)
- M J Klouwens
- Department of Internal Medicine, Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. .,Division of Infectious Diseases, Department of Internal Medicine, Academic Medical Center, Amsterdam, The Netherlands. .,Amsterdam Multidisciplinary Lyme Borreliosis Center, Academic Medical Center, Amsterdam, The Netherlands.
| | - J J Trentelman
- Department of Internal Medicine, Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - J I Ersoz
- Department of Internal Medicine, Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - F Nieves Marques Porto
- Department of Internal Medicine, Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - R Sima
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - O Hajdusek
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - M Thakur
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia- Maryland Regional College of Veterinary Medicine, College Park, MD, USA
| | - U Pal
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia- Maryland Regional College of Veterinary Medicine, College Park, MD, USA
| | - J W Hovius
- Department of Internal Medicine, Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.,Division of Infectious Diseases, Department of Internal Medicine, Academic Medical Center, Amsterdam, The Netherlands.,Amsterdam Multidisciplinary Lyme Borreliosis Center, Academic Medical Center, Amsterdam, The Netherlands
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5
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Bista S, Singh P, Bernard Q, Yang X, Hart T, Lin YP, Kitsou C, Singh Rana V, Zhang F, Linhardt RJ, Zhnag K, Akins DR, Hritzo L, Kim Y, Grab DJ, Dumler JS, Pal U. A Novel Laminin-Binding Protein Mediates Microbial-Endothelial Cell Interactions and Facilitates Dissemination of Lyme Disease Pathogens. J Infect Dis 2021; 221:1438-1447. [PMID: 31758693 DOI: 10.1093/infdis/jiz626] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 11/21/2019] [Indexed: 12/13/2022] Open
Abstract
Borrelia burgdorferi conserved gene products BB0406 and BB0405, members of a common B. burgdorferi paralogous gene family, share 59% similarity. Although both gene products can function as potential porins, only BB0405 is essential for infection. Here we show that, despite sequence homology and coexpression from the same operon, both proteins differ in their membrane localization attributes, antibody accessibility, and immunogenicity in mice. BB0406 is required for spirochete survival in mammalian hosts, particularly for the disseminated infection in distant organs. We identified that BB0406 interacts with laminin, one of the major constituents of the vascular basement membrane, and facilitates spirochete transmigration across host endothelial cell barriers. A better understanding of how B. burgdorferi transmigrates through dermal and tissue vascular barriers and establishes disseminated infections will contribute to the development of novel therapeutics to combat early infection.
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Affiliation(s)
- Sandhya Bista
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland, USA
| | - Preeti Singh
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland, USA
| | - Quentin Bernard
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland, USA
| | - Xiuli Yang
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland, USA
| | - Thomas Hart
- Department of Biological Science, State University of New York at Albany, Albany, New York, USA.,Division of Infectious Diseases, Wadsworth Center New York State Department of Health, Albany, New York, USA
| | - Yi-Pin Lin
- Department of Biological Science, State University of New York at Albany, Albany, New York, USA.,Department of Biomedical Science, State University of New York at Albany, Albany, New York, USA
| | - Chrysoula Kitsou
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland, USA
| | - Vipin Singh Rana
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland, USA
| | - Fuming Zhang
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Robert J Linhardt
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York, USA.,Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York, USA.,Department of Biology and Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Kai Zhnag
- Oral and Craniofacial Molecular Biology, School of Dentistry, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Darrin R Akins
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Lucy Hritzo
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Yuri Kim
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Dennis J Grab
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - J Stephen Dumler
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland, USA.,Virginia-Maryland College of Veterinary Medicine, College Park, Maryland
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6
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Pal U, Kitsou C, Drecktrah D, Yaş ÖB, Fikrig E. Interactions Between Ticks and Lyme Disease Spirochetes. Curr Issues Mol Biol 2020; 42:113-144. [PMID: 33289683 DOI: 10.21775/cimb.042.113] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Borrelia burgdorferi sensu lato causes Lyme borreliosis in a variety of animals and humans. These atypical bacterial pathogens are maintained in a complex enzootic life cycle that primarily involves a vertebrate host and Ixodes spp. ticks. In the Northeastern United States, I. scapularis is the main vector, while wild rodents serve as the mammalian reservoir host. As B. burgdorferi is transmitted only by I. scapularis and closely related ticks, the spirochete-tick interactions are thought to be highly specific. Various borrelial and arthropod proteins that directly or indirectly contribute to the natural cycle of B. burgdorferi infection have been identified. Discrete molecular interactions between spirochetes and tick components also have been discovered, which often play critical roles in pathogen persistence and transmission by the arthropod vector. This review will focus on the past discoveries and future challenges that are relevant to our understanding of the molecular interactions between B. burgdorferi and Ixodes ticks. This information will not only impact scientific advancements in the research of tick- transmitted infections but will also contribute to the development of novel preventive measures that interfere with the B. burgdorferi life cycle.
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Affiliation(s)
- Utpal Pal
- Department of Veterinary Medicine, University of Maryland, 8075 Greenmead Drive, College Park, MD 20742, USA
| | - Chrysoula Kitsou
- Department of Veterinary Medicine, University of Maryland, 8075 Greenmead Drive, College Park, MD 20742, USA
| | - Dan Drecktrah
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Özlem Büyüktanir Yaş
- Department of Microbiology and Clinical Microbiology, Faculty of Medicine, Istinye University, Zeytinburnu, İstanbul, 34010, Turkey
| | - Erol Fikrig
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
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7
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Bernard Q, Phelan JP, Hu LT. Controlling Lyme Disease: New Paradigms for Targeting the Tick-Pathogen-Reservoir Axis on the Horizon. Front Cell Infect Microbiol 2020; 10:607170. [PMID: 33344266 PMCID: PMC7744311 DOI: 10.3389/fcimb.2020.607170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/04/2020] [Indexed: 11/20/2022] Open
Affiliation(s)
| | | | - Linden T. Hu
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, United States
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8
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Yang X, Koči J, Smith AA, Zhuang X, Sharma K, Dutta S, Rana VS, Kitsou C, Yas OB, Mongodin EF, Pal U. A novel tick protein supports integrity of gut peritrophic matrix impacting existence of gut microbiome and Lyme disease pathogens. Cell Microbiol 2020; 23:e13275. [PMID: 33006213 DOI: 10.1111/cmi.13275] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 01/09/2023]
Abstract
The peritrophic matrix (PM) is an acellular membrane that covers the gut epithelium in arthropods and physically separates it from the lumen. The structure is thought to play an important role in tick biology. The PM is also known to impact the persistence of tick-borne pathogens like Borrelia burgdorferi, although limited information is available about its molecular constituents or their biological significance. Herein, we characterise a novel PM-associated gut protein in Ixodes scapularis ticks, annotated as Peritrophic Membrane Chitin Binding Protein (PM_CBP), for its role in the integrity and function of the matrix. The PM_CBP displays homology to the chitin deacetylase metalloenzyme, shows upregulation during tick feeding, and is localized at the luminal surface of the gut epithelium. The structural integrity of the PM was impaired both by the knock down of PM_CBP expression via RNA interference and by treatment with anti-PM_CBP antibodies, as revealed by its electron microscopic appearance. Additionally, the duration of tick engorgement on mice and the passage of experimentally-inoculated fluorescent dextran molecules across the PM are affected by the knock down of PM_CBP expression. The transfer of anti-PM_CBP antibodies into the tick gut impacted the overall composition of the resident microbiome, and also influenced B. burgdorferi acquisition in ticks and its transmission to mice. Taken together, these data highlight the biological significance of the Ixodes PM and suggest that the targeting of its molecular constituents may contribute to the development of novel interventions against tick-borne infections.
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Affiliation(s)
- Xiuli Yang
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, Maryland, USA
| | - Juraj Koči
- Institute of Zoology, Slovak Academy of Sciences, Bratislava, Slovakia.,Institute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Alexis A Smith
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, Maryland, USA
| | - Xuran Zhuang
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, Maryland, USA
| | - Kavita Sharma
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, Maryland, USA
| | - Shraboni Dutta
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, Maryland, USA
| | - Vipin S Rana
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, Maryland, USA
| | - Chrysoula Kitsou
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, Maryland, USA
| | - Ozlem B Yas
- Department of Microbiology and Clinical Microbiology, Faculty of Medicine, Istinye University, İstanbul, Turkey
| | - Emmanuel F Mongodin
- Institute for Genome Sciences and Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, Maryland, USA.,Virginia-Maryland Regional College of Veterinary Medicine, College Park, Maryland, USA
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9
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Lin YP, Tan X, Caine JA, Castellanos M, Chaconas G, Coburn J, Leong JM. Strain-specific joint invasion and colonization by Lyme disease spirochetes is promoted by outer surface protein C. PLoS Pathog 2020; 16:e1008516. [PMID: 32413091 PMCID: PMC7255614 DOI: 10.1371/journal.ppat.1008516] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/28/2020] [Accepted: 04/03/2020] [Indexed: 01/06/2023] Open
Abstract
Lyme disease, caused by Borrelia burgdorferi, B. afzelii and B. garinii, is a chronic, multi-systemic infection and the spectrum of tissues affected can vary with the Lyme disease strain. For example, whereas B. garinii infection is associated with neurologic manifestations, B. burgdorferi infection is associated with arthritis. The basis for tissue tropism is poorly understood, but has been long hypothesized to involve strain-specific interactions with host components in the target tissue. OspC (outer surface protein C) is a highly variable outer surface protein required for infectivity, and sequence differences in OspC are associated with variation in tissue invasiveness, but whether OspC directly influences tropism is unknown. We found that OspC binds to the extracellular matrix (ECM) components fibronectin and/or dermatan sulfate in an OspC variant-dependent manner. Murine infection by isogenic B. burgdorferi strains differing only in their ospC coding region revealed that two OspC variants capable of binding dermatan sulfate promoted colonization of all tissues tested, including joints. However, an isogenic strain producing OspC from B. garinii strain PBr, which binds fibronectin but not dermatan sulfate, colonized the skin, heart and bladder, but not joints. Moreover, a strain producing an OspC altered to recognize neither fibronectin nor dermatan sulfate displayed dramatically reduced levels of tissue colonization that were indistinguishable from a strain entirely deficient in OspC. Finally, intravital microscopy revealed that this OspC mutant, in contrast to a strain producing wild type OspC, was defective in promoting joint invasion by B. burgdorferi in living mice. We conclude that OspC functions as an ECM-binding adhesin that is required for joint invasion, and that variation in OspC sequence contributes to strain-specific differences in tissue tropism displayed among Lyme disease spirochetes. Infection by different Lyme disease bacteria is associated with different manifestations, such as cardiac, neurologic, or, in the case of B. burgdorferi, the major cause of Lyme disease in the U.S., joint disease. The basis for these differences is unknown, but likely involve strain-specific interactions with host components in the target tissue. The sequence of the outer surface lipoprotein OspC varies with the strains, and we found that this variation influences the spectrum of host extracellular matrix components recognized. Infection of mice with strains that are identical except for ospC revealed that OspC variants that differ in binding spectrum promote infection of different tissues. A strain producing OspC invaded and colonized the joint in living animals, but an altered OspC protein incapable of binding tissue components did not. Thus, tissue-binding by OspC is critical for infection and joint invasion, and OspC variation directly influences tissue tropism.
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Affiliation(s)
- Yi-Pin Lin
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Division of Infectious Diseases, New York State Department of Health, Wadsworth Center, Albany, New York, United States of America
| | - Xi Tan
- Departments of Biochemistry & Molecular Biology and Microbiology, Immunology & Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Jennifer A. Caine
- Division of Infectious Diseases, and Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Mildred Castellanos
- Departments of Biochemistry & Molecular Biology and Microbiology, Immunology & Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - George Chaconas
- Departments of Biochemistry & Molecular Biology and Microbiology, Immunology & Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Jenifer Coburn
- Division of Infectious Diseases, and Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- * E-mail: (JC); (JML)
| | - John M. Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail: (JC); (JML)
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10
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Winslow C, Coburn J. Recent discoveries and advancements in research on the Lyme disease spirochete Borrelia burgdorferi. F1000Res 2019; 8. [PMID: 31214329 PMCID: PMC6545822 DOI: 10.12688/f1000research.18379.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/20/2019] [Indexed: 12/26/2022] Open
Abstract
This review highlights some of the highest-profile developments and advancements in the research on
Borrelia burgdorferi, the Lyme disease spirochete, that have emerged in the last two years. Particular emphasis is placed on the controversy surrounding genus nomenclature, antigenic variation at the
vlsE locus, genes involved in infectivity and virulence, membrane characteristics of
B. burgdorferi, and developments in experimental approaches.
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Affiliation(s)
- Christa Winslow
- Department of Microbiology and Immunology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Jenifer Coburn
- Department of Microbiology and Immunology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.,Department of Medicine, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
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11
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Tyler S, Tyson S, Dibernardo A, Drebot M, Feil EJ, Graham M, Knox NC, Lindsay LR, Margos G, Mechai S, Van Domselaar G, Thorpe HA, Ogden NH. Whole genome sequencing and phylogenetic analysis of strains of the agent of Lyme disease Borrelia burgdorferi from Canadian emergence zones. Sci Rep 2018; 8:10552. [PMID: 30002414 PMCID: PMC6043495 DOI: 10.1038/s41598-018-28908-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 06/27/2018] [Indexed: 12/19/2022] Open
Abstract
Lyme disease is emerging in southern Canada due to range expansion of the tick vector, followed by invasion of the agent of Lyme disease Borrelia burgdorferi sensu stricto. Strain diversity, as determined by Multi Locus Sequence Typing, occurs in this zone of emergence, and this may have its origins in adaptation to ecological niches, and have phenotypic consequences for pathogenicity and serological test performance. Sixty-four unique strains were cultured from ticks collected in southern Canada and the genomes sequenced using the Illumina MiSeq platform. A maximum likelihood phylogenetic tree of the chromosome revealed two large clades with multiple subclades. Consistent with previous studies on this species, the clades were not geographically defined, and some Canadian strains were highly divergent from previously sequenced US strains. There was evidence for recombination in the chromosome but this did not affect the phylogeny. Analysis of chromosomal genes indicated that these are under intense purifying selection. Phylogenies of the accessory genome and chromosome were congruent. Therefore strain differences identified in the phylogeny of chromosomal genes likely act as a proxy for genetic determinants of phenotypic differences amongst strains that are harboured in the accessory genome. Further studies on health implications of strain diversity are needed.
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Affiliation(s)
- Shaun Tyler
- Genomics Core Facility, National Microbiology Laboratory, Public Health Agency of Canada, Canadian Science Centre for Human and Animal Health, 1015, Arlington St., Winnipeg, Manitoba, Canada
| | - Shari Tyson
- Genomics Core Facility, National Microbiology Laboratory, Public Health Agency of Canada, Canadian Science Centre for Human and Animal Health, 1015, Arlington St., Winnipeg, Manitoba, Canada
| | - Antonia Dibernardo
- Zoonotic Diseases and Special Pathogens Division, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Michael Drebot
- Zoonotic Diseases and Special Pathogens Division, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Edward J Feil
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, United Kingdom
| | - Morag Graham
- Genomics Core Facility, National Microbiology Laboratory, Public Health Agency of Canada, Canadian Science Centre for Human and Animal Health, 1015, Arlington St., Winnipeg, Manitoba, Canada
| | - Natalie C Knox
- Genomics Core Facility, National Microbiology Laboratory, Public Health Agency of Canada, Canadian Science Centre for Human and Animal Health, 1015, Arlington St., Winnipeg, Manitoba, Canada
| | - L Robbin Lindsay
- Zoonotic Diseases and Special Pathogens Division, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Gabriele Margos
- Ludwig Maximilians Universität München, Department for Infectious Diseases and Zoonoses, Munich, Germany.,National Reference Centre for Borrelia, Oberschleissheim and Bavarian Health and Food Safety Authority, Oberschleissheim, Germany
| | - Samir Mechai
- Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, Saint-Hyacinthe, Québec, J2S 2M2, Canada
| | - Gary Van Domselaar
- Genomics Core Facility, National Microbiology Laboratory, Public Health Agency of Canada, Canadian Science Centre for Human and Animal Health, 1015, Arlington St., Winnipeg, Manitoba, Canada
| | - Harry A Thorpe
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, United Kingdom
| | - Nick H Ogden
- Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, Saint-Hyacinthe, Québec, J2S 2M2, Canada.
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12
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Bernard Q, Thakur M, Smith AA, Kitsou C, Yang X, Pal U. Borrelia burgdorferi protein interactions critical for microbial persistence in mammals. Cell Microbiol 2018; 21:e12885. [PMID: 29934966 PMCID: PMC10082445 DOI: 10.1111/cmi.12885] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Revised: 06/11/2018] [Accepted: 06/14/2018] [Indexed: 12/24/2022]
Abstract
Borrelia burgdorferi is the causative agent of Lyme disease that persists in a complex enzootic life cycle, involving Ixodes ticks and vertebrate hosts. The microbe invades ticks and vertebrate hosts in spite of active immune surveillance and potent microbicidal responses, and establishes long-term infection utilising mechanisms that are yet to be unravelled. The pathogen can cause multi-system disorders when transmitted to susceptible mammalian hosts, including in humans. In the past decades, several studies identified a limited number of B. burgdorferi gene-products critical for pathogen persistence, transmission between the vectors and the host, and host-pathogen interactions. This review will focus on the interactions between B. burgdorferi proteins, as well as between microbial proteins and host components, protein and non-protein components, highlighting their roles in pathogen persistence in the mammalian host. A better understanding of the contributions of protein interactions in the microbial virulence and persistence of B. burgdorferi would support development of novel therapeutics against the infection.
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Affiliation(s)
- Quentin Bernard
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland
| | - Meghna Thakur
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland
| | - Alexis A Smith
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland
| | - Chrysoula Kitsou
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland
| | - Xiuli Yang
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland, College Park, Maryland
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13
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Zhuang X, Yang X, Altieri AS, Nelson DC, Pal U. Borrelia burgdorferi surface-located Lmp1 protein processed into region-specific polypeptides that are critical for microbial persistence. Cell Microbiol 2018; 20:e12855. [PMID: 29749010 DOI: 10.1111/cmi.12855] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 03/24/2018] [Accepted: 04/18/2018] [Indexed: 12/21/2022]
Abstract
One of the Borrelia burgdorferi virulence determinants, annotated as Lmp1, is a surface-exposed, conserved, and potential multi-domain protein involved in various functions in spirochete infectivity. Lmp1 contributes to host-pathogen interactions and evasion of host adaptive immunity by spirochetes. Here, we show that in diverse B. burgdorferi species, Lmp1 exists as distinct, region-specific, and lower molecular mass polypeptides encompassing 1 or more domains, including independent N-terminal and middle regions and a combined middle and C-terminal region. These polypeptides originate from complex posttranslational maturation events, partly supported by a periplasmic serine protease termed as BbHtrA. Although spirochete persistence in mice is independently supported by domain-specific Lmp1 polypeptides, transmission of B. burgdorferi from ticks to mammals requires essential contributions from both N-terminal and middle regions. Interference with the functions of Lmp1 domains or their complex posttranslational maturation events may aid in development of novel therapeutic strategies to combat infection and transmission of pathogens.
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Affiliation(s)
- Xuran Zhuang
- Department of Veterinary Medicine, University of Maryland, College Park, MD, USA
| | - Xiuli Yang
- Department of Veterinary Medicine, University of Maryland, College Park, MD, USA
| | - Amanda S Altieri
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA.,National Institute for Standards and Technology, Gaithersburg, MD, USA
| | - Daniel C Nelson
- Department of Veterinary Medicine, University of Maryland, College Park, MD, USA.,Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland, College Park, MD, USA.,Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD, USA
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14
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Plasticity in early immune evasion strategies of a bacterial pathogen. Proc Natl Acad Sci U S A 2018; 115:E3788-E3797. [PMID: 29610317 DOI: 10.1073/pnas.1718595115] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Borrelia burgdorferi is one of the few extracellular pathogens capable of establishing persistent infection in mammals. The mechanisms that sustain long-term survival of this bacterium are largely unknown. Here we report a unique innate immune evasion strategy of B. burgdorferi, orchestrated by a surface protein annotated as BBA57, through its modulation of multiple spirochete virulent determinants. BBA57 function is critical for early infection but largely redundant for later stages of spirochetal persistence, either in mammals or in ticks. The protein influences host IFN responses as well as suppresses multiple host microbicidal activities involving serum complement, neutrophils, and antimicrobial peptides. We also discovered a remarkable plasticity in BBA57-mediated spirochete immune evasion strategy because its loss, although resulting in near clearance of pathogens at the inoculum site, triggers nonheritable adaptive changes that exclude detectable nucleotide alterations in the genome but incorporate transcriptional reprograming events. Understanding the malleability in spirochetal immune evasion mechanisms that ensures their host persistence is critical for the development of novel therapeutic and preventive approaches to combat long-term infections like Lyme borreliosis.
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15
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Borrelia burgdorferi surface protein Lmp1 facilitates pathogen dissemination through ticks as studied by an artificial membrane feeding system. Sci Rep 2018; 8:1910. [PMID: 29382879 PMCID: PMC5790009 DOI: 10.1038/s41598-018-20208-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 01/15/2018] [Indexed: 12/17/2022] Open
Abstract
In its natural infection cycle, the pathogen of Lyme borreliosis transits between a tick vector and a mammalian host. As relatively a minor fraction of spirochetes transits between the host and the vector precluding their reliable detection at early infection, artificial membrane feeders emerged as useful tools to study roles of spirochete proteins in pathogen entry, persistence, and exit through ticks. Here we report the development of a modified membrane feeder to study the role of a Borrelia burgdorferi surface protein called Lmp1 in spirochete transitions between the murine host and ticks. We show that our membrane feeder supports the blood meal engorgement process where ticks can acquire spirochetes from the feeder containing extremely low levels of pathogens (102 cells/ml of blood). Our data revealed that in comparison to wild-type spirochetes, lmp1 deletion mutants are significantly impaired for acquisition in naïve ticks as well as transmission from infected ticks. Taking together, our data suggest that Lmp1 plays an essential role in spirochete transitions between hosts and the vector. These studies also underscore the usefulness of artificial membrane feeding system as a valuable tool to study the role of B. burgdorferi gene-products in pathogen persistence in and passage through vector ticks.
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16
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Artificial Infection of Ticks with Borrelia burgdorferi Using a Microinjection Method and Their Detection In Vivo Using Quantitative PCR Targeting flaB RNA. Methods Mol Biol 2018; 1690:105-114. [PMID: 29032540 DOI: 10.1007/978-1-4939-7383-5_9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Borrelia burgdorferi is maintained in nature by a tick-rodent infection cycle where it traverses and colonizes a variety of host and vector tissues. A tick-borne murine model has been developed to study Lyme disease in the laboratory, which has a substantial impact in advancing our knowledge of spirochete infectivity and pathogenesis. Here, we detail a microinjection-based method for rapid and efficient infection of ticks with B. burgdorferi. While laboratory generation of B. burgdorferi-infected nymphs via natural larval engorgement on infected hosts and subsequent molting could take several weeks to months, the microinjection-based infection procedure requires only a few hours to generate infected ticks and allows introduction of defined quantities of spirochetes, including mutant isolates that are attenuated for infection in mice and thus cannot be naturally acquired by ticks. We also describe a quantitative PCR-based protocol for the measurement of B. burgdorferi in tick and murine hosts targeting spirochete RNA that is highly efficient, reproducible, and a better surrogate of active infection.
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17
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Lin YP, Li L, Zhang F, Linhardt RJ. Borrelia burgdorferi glycosaminoglycan-binding proteins: a potential target for new therapeutics against Lyme disease. MICROBIOLOGY-SGM 2017; 163:1759-1766. [PMID: 29116038 DOI: 10.1099/mic.0.000571] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The spirochete bacterium Borrelia burgdorferi sensu lato is the causative agent of Lyme disease, the most common vector-borne disease in Europe and the United States. The spirochetes can be transmitted to humans via ticks, and then spread to different tissues, leading to arthritis, carditis and neuroborreliosis. Although antibiotics have commonly been used to treat infected individuals, some treated patients do not respond to antibiotics and experience persistent, long-term arthritis. Thus, there is a need to investigate alternative therapeutics against Lyme disease. The spirochete bacterium colonization is partly attributed to the binding of the bacterial outer-surface proteins to the glycosaminoglycan (GAG) chains of host proteoglycans. Blocking the binding of these proteins to GAGs is a potential strategy to prevent infection. In this review, we have summarized the recent reports of B. burgdorferi sensu lato GAG-binding proteins and discussed the potential use of synthetic and semi-synthetic compounds, including GAG analogues, to block pathogen interaction with GAGs. Such information should motivate the discovery and development of novel GAG analogues as new therapeutics for Lyme disease. New therapeutic approaches should eventually reduce the burden of Lyme disease and improve human health.
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Affiliation(s)
- Yi-Pin Lin
- Department of Biomedical Science, State University of New York at Albany, Albany, NY, USA.,Division of Infectious Disease, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Lingyun Li
- Division of Environmental Health Science, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Fuming Zhang
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Robert J Linhardt
- Departments of Biology and Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA.,Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA.,Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
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18
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Singh P, Verma D, Backstedt BT, Kaur S, Kumar M, Smith AA, Sharma K, Yang X, Azevedo JF, Gomes-Solecki M, Buyuktanir O, Pal U. Borrelia burgdorferi BBI39 Paralogs, Targets of Protective Immunity, Reduce Pathogen Persistence Either in Hosts or in the Vector. J Infect Dis 2017; 215:1000-1009. [PMID: 28453837 DOI: 10.1093/infdis/jix036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 01/16/2017] [Indexed: 01/01/2023] Open
Abstract
Borrelia burgdorferi genome harbors several paralogous gene families (pgf) that can encode immunogenic proteins of unknown function. Protein-protein interaction assays using a transmission-blocking vaccine candidate, BBA52, as bait identified an interacting partner in spirochetes-a member of pgf 54, annotated as BBI39. We show that BBI39 is a surface-exposed membrane antigen that is immunogenic during spirochete infection, despite the gene being primarily transcribed in the vector with a transient expression in the host only at tick-bite sites. Immunization of rodents with BBI39, or a diverse paralog, BBI36, or their combination impaired pathogen acquisition by the vector, transmission from ticks to hosts, or induction of disease. High-titer BBI39 immunoglobulin G antibodies, which have borreliacidal properties, could be generated through routine subcutaneous or oral immunization, further highlighting use of BBI39 proteins as novel Lyme disease vaccines that can target pathogens in the host or in ticks.
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Affiliation(s)
- Preeti Singh
- Department of Veterinary Medicine, University of Maryland and Virginia-Maryland, Regional College of Veterinary Medicine, College Park, Maryland, USA
| | - Deepshikha Verma
- Department of Veterinary Medicine, University of Maryland and Virginia-Maryland, Regional College of Veterinary Medicine, College Park, Maryland, USA
| | - Brian T Backstedt
- Department of Veterinary Medicine, University of Maryland and Virginia-Maryland, Regional College of Veterinary Medicine, College Park, Maryland, USA
| | - Simarjot Kaur
- Department of Veterinary Medicine, University of Maryland and Virginia-Maryland, Regional College of Veterinary Medicine, College Park, Maryland, USA
| | - Manish Kumar
- Department of Veterinary Medicine, University of Maryland and Virginia-Maryland, Regional College of Veterinary Medicine, College Park, Maryland, USA
| | - Alexis A Smith
- Department of Veterinary Medicine, University of Maryland and Virginia-Maryland, Regional College of Veterinary Medicine, College Park, Maryland, USA
| | - Kavita Sharma
- Department of Veterinary Medicine, University of Maryland and Virginia-Maryland, Regional College of Veterinary Medicine, College Park, Maryland, USA
| | - Xiuli Yang
- Department of Veterinary Medicine, University of Maryland and Virginia-Maryland, Regional College of Veterinary Medicine, College Park, Maryland, USA
| | | | - Maria Gomes-Solecki
- Immuno Technologies Inc., Memphis, Tennessee, USA.,Department of Microbiology, Immunology and Biochemistry, College of Medicine, University of Tennessee Health Sciences Center, Memphis, Tennessee, USA
| | - Ozlem Buyuktanir
- Department of Microbiology, Faculty of Veterinary Medicine, Ondokuz Mayis University, Samsun, Turkey
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland and Virginia-Maryland, Regional College of Veterinary Medicine, College Park, Maryland, USA
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19
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Outer Membrane Proteins BB0405 and BB0406 Are Immunogenic, but Only BB0405 Is Required for Borrelia burgdorferi Infection. Infect Immun 2017; 85:IAI.00803-16. [PMID: 27920211 DOI: 10.1128/iai.00803-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 11/24/2016] [Indexed: 02/06/2023] Open
Abstract
We recently identified the Borrelia burgdorferi outer membrane protein (OMP) BB0406 and found that the gene encoding this OMP was cotranscribed with the gene encoding the OMP BB0405. Interestingly, BB0405 and BB0406 share 59% similarity and are grouped into the same B. burgdorferi paralogous gene family. Given their overall similarity, it is plausible that both OMPs have similar or overlapping functions in this pathogenic spirochete. BB0405 was recently shown to be required for mammalian infection despite the observations that BB0405 is poorly immunogenic and not recognized during mouse or human infection. BB0405 orthologs have also been shown to bind the complement regulator protein factor H. Therefore, to better elucidate the role of BB0405 and its paralog BB0406 during infection and in serum resistance, we examined both proteins in animal infection, factor H binding, and serum sensitivity assays. Our combined results suggest that BB0405- and BB0406-specific antibodies are borreliacidal and that both OMPs are immunogenic during nonhuman primate infection. Additionally, while BB0405 was found to be required for establishing mouse infection, BB0406 was not found to be essential for infectivity. In contrast to data from previous reports, however, neither OMP was found to bind human factor H or to be required for enhancing serum resistance of B. burgdorferi in vitro.
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20
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Caine JA, Coburn J. Multifunctional and Redundant Roles of Borrelia burgdorferi Outer Surface Proteins in Tissue Adhesion, Colonization, and Complement Evasion. Front Immunol 2016; 7:442. [PMID: 27818662 PMCID: PMC5073149 DOI: 10.3389/fimmu.2016.00442] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 10/07/2016] [Indexed: 12/24/2022] Open
Abstract
Borrelia burgdorferi is the causative agent of Lyme disease in the U.S., with at least 25,000 cases reported to the CDC each year. B. burgdorferi is thought to enter and exit the bloodstream to achieve rapid dissemination to distal tissue sites during infection. Travel through the bloodstream requires evasion of immune surveillance and pathogen clearance in the host, a process at which B. burgdorferi is adept. B. burgdorferi encodes greater than 19 adhesive outer surface proteins many of which have been found to bind to host cells or components of the extracellular matrix. Several others bind to host complement regulatory factors, in vitro. Production of many of these adhesive proteins is tightly regulated by environmental cues, and some have been shown to aid in vascular interactions and tissue colonization, as well as survival in the blood, in vivo. Recent work has described multifaceted and redundant roles of B. burgdorferi outer surface proteins in complement component interactions and tissue targeted adhesion and colonization, distinct from their previously identified in vitro binding capabilities. Recent insights into the multifunctional roles of previously well-characterized outer surface proteins such as BBK32, DbpA, CspA, and OspC have changed the way we think about the surface proteome of these organisms during the tick-mammal life cycle. With the combination of new and old in vivo models and in vitro techniques, the field has identified distinct ligand binding domains on BBK32 and DbpA that afford tissue colonization or blood survival to B. burgdorferi. In this review, we describe the multifunctional and redundant roles of many adhesive outer surface proteins of B. burgdorferi in tissue adhesion, colonization, and bloodstream survival that, together, promote the survival of Borrelia spp. throughout maintenance in their multi-host lifestyle.
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Affiliation(s)
- Jennifer A. Caine
- Division of Infectious Disease, Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Jenifer Coburn
- Division of Infectious Disease, Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, WI, USA
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21
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HtrA, a Temperature- and Stationary Phase-Activated Protease Involved in Maturation of a Key Microbial Virulence Determinant, Facilitates Borrelia burgdorferi Infection in Mammalian Hosts. Infect Immun 2016; 84:2372-2381. [PMID: 27271745 DOI: 10.1128/iai.00360-16] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 05/31/2016] [Indexed: 01/04/2023] Open
Abstract
High-temperature requirement protease A (HtrA) represents a family of serine proteases that play important roles in microbial biology. Unlike the genomes of most organisms, that of Borrelia burgdorferi notably encodes a single HtrA gene product, termed BbHtrA. Previous studies identified a few substrates of BbHtrA; however, their physiological relevance could not be ascertained, as targeted deletion of the gene has not been successful. Here we show that BbhtrA transcripts are induced during spirochete growth either in the stationary phase or at elevated temperature. Successful generation of a BbhtrA deletion mutant and restoration by genetic complementation suggest a nonessential role for this protease in microbial viability; however, its remarkable growth, morphological, and structural defects during cultivation at 37°C confirm a high-temperature requirement for protease activation and function. The BbhtrA-deficient spirochetes were unable to establish infection of mice, as evidenced by assessment of culture, PCR, and serology. We show that transcript abundance as well as proteolytic processing of a borrelial protein required for cell fission and infectivity, BB0323, is impaired in BbhtrA mutants grown at 37°C, which likely contributed to their inability to survive in a mammalian host. Together, these results demonstrate the physiological relevance of a unique temperature-regulated borrelial protease, BbHtrA, which further enlightens our knowledge of intriguing aspects of spirochete biology and infectivity.
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22
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Kenedy MR, Scott EJ, Shrestha B, Anand A, Iqbal H, Radolf JD, Dyer DW, Akins DR. Consensus computational network analysis for identifying candidate outer membrane proteins from Borrelia spirochetes. BMC Microbiol 2016; 16:141. [PMID: 27400788 PMCID: PMC4939628 DOI: 10.1186/s12866-016-0762-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 07/02/2016] [Indexed: 01/15/2023] Open
Abstract
Background Similar to Gram-negative organisms, Borrelia spirochetes are dual-membrane organisms with both an inner and outer membrane. Although the outer membrane contains integral membrane proteins, few of the borrelial outer membrane proteins (OMPs) have been identified and characterized to date. Therefore, we utilized a consensus computational network analysis to identify novel borrelial OMPs. Results Using a series of computer-based algorithms, we selected all protein-encoding sequences predicted to be OM-localized and/or to form β-barrels in the borrelial OM. Using this system, we identified 41 potential OMPs from B. burgdorferi and characterized three (BB0838, BB0405, and BB0406) to confirm that our computer-based methodology did, in fact, identify borrelial OMPs. Triton X-114 phase partitioning revealed that BB0838 is found in the detergent phase, which would be expected of a membrane protein. Proteolysis assays indicate that BB0838 is partially sensitive to both proteinase K and trypsin, further indicating that BB0838 is surface-exposed. Consistent with a prior study, we also confirmed that BB0405 is surface-exposed and associates with the borrelial OM. Furthermore, we have shown that BB0406, the product of a co-transcribed downstream gene, also encodes a novel, previously uncharacterized borrelial OMP. Interestingly, while BB0406 has several physicochemical properties consistent with it being an OMP, it was found to be resistant to surface proteolysis. Consistent with BB0405 and BB0406 being OMPs, both were found to be capable of incorporating into liposomes and exhibit pore-forming activity, suggesting that both proteins are porins. Lastly, we expanded our computational analysis to identify OMPs from other borrelial organisms, including both Lyme disease and relapsing fever spirochetes. Conclusions Using a consensus computer algorithm, we generated a list of candidate OMPs for both Lyme disease and relapsing fever spirochetes and determined that three of the predicted B. burgdorferi proteins identified were indeed novel borrelial OMPs. The combined studies have identified putative spirochetal OMPs that can now be examined for their roles in virulence, physiology, and disease pathogenesis. Importantly, the studies described in this report provide a framework by which OMPs from any human pathogen with a diderm ultrastructure could be cataloged to identify novel virulence factors and vaccine candidates. Electronic supplementary material The online version of this article (doi:10.1186/s12866-016-0762-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Melisha R Kenedy
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, USA
| | - Edgar J Scott
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, USA
| | - Binu Shrestha
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, USA
| | - Arvind Anand
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, 06030, USA
| | - Henna Iqbal
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, USA
| | - Justin D Radolf
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut, 06030, USA.,Department of Pediatrics, University of Connecticut Health Center, Farmington, Connecticut, 06030, USA.,Department of Genetics and Genomic Science, University of Connecticut Health Center, Farmington, Connecticut, 06030, USA.,Department of Immunology, University of Connecticut Health Center, Farmington, Connecticut, 06030, USA.,Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, 06030, USA
| | - David W Dyer
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, USA
| | - Darrin R Akins
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, USA.
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23
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Kung F, Kaur S, Smith AA, Yang X, Wilder CN, Sharma K, Buyuktanir O, Pal U. A Borrelia burgdorferi Surface-Exposed Transmembrane Protein Lacking Detectable Immune Responses Supports Pathogen Persistence and Constitutes a Vaccine Target. J Infect Dis 2016; 213:1786-95. [PMID: 26747708 DOI: 10.1093/infdis/jiw013] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 12/30/2015] [Indexed: 01/29/2023] Open
Abstract
Borrelia burgdorferi harbors a limited set of transmembrane surface proteins, most of which constitute key targets of humoral immune responses. Here we show that BB0405, a conserved membrane-spanning protein of unknown function, fails to evoke detectable antibody responses despite its extracellular exposure. bb0405 is a member of an operon and ubiquitously expressed throughout the rodent-tick infection cycle. The gene product serves an essential function in vivo, as bb0405-deletion mutants are unable to transmit from ticks and establish infection in mammalian hosts. Despite the lack of BB0405-specific immunoglobulin M or immunoglobulin G antibodies during natural infection, mice immunized with a recombinant version of the protein elicited high-titer and remarkably long-lasting antibody responses, conferring significant host protection against tick-borne infection. Taken together, these studies highlight the essential role of an apparently immune-invisible borrelial transmembrane protein in facilitating infection and its usefulness as a target of protective host immunity blocking the transmission of B. burgdorferi.
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Affiliation(s)
- Faith Kung
- Department of Veterinary Medicine, University of Maryland-College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park
| | - Simarjot Kaur
- Department of Veterinary Medicine, University of Maryland-College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park
| | - Alexis A Smith
- Department of Veterinary Medicine, University of Maryland-College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park
| | - Xiuli Yang
- Department of Veterinary Medicine, University of Maryland-College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park
| | - Cara N Wilder
- Department of Veterinary Medicine, University of Maryland-College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park
| | - Kavita Sharma
- Department of Veterinary Medicine, University of Maryland-College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park
| | - Ozlem Buyuktanir
- Department of Microbiology, Faculty of Veterinary Medicine, Ondokuz Mayis University, Samsun, Turkey
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland-College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park
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24
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Borrelia burgdorferi elongation factor EF-Tu is an immunogenic protein during Lyme borreliosis. Emerg Microbes Infect 2015; 4:e54. [PMID: 26954993 PMCID: PMC5176084 DOI: 10.1038/emi.2015.54] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 07/17/2015] [Accepted: 07/21/2015] [Indexed: 12/22/2022]
Abstract
Borrelia burgdorferi, the etiological agent of Lyme disease, does not produce lipopolysaccharide but expresses a large number of lipoproteins on its cell surface. These outer membrane lipoproteins are highly immunogenic and have been used for serodiagnosis of Lyme disease. Recent studies have shown that highly conserved cytosolic proteins such as enolase and elongation factor Tu (EF-Tu) unexpectedly localized on the surface of bacteria including B. burgdorferi, and surface-localized enolase has shown to contribute to the enzootic cycle of B. burgdorferi. In this study, we studied the immunogenicity, surface localization, and function of B. burgdorferi EF-Tu. We found that EF-Tu is highly immunogenic in mice, and EF-Tu antibodies were readily detected in Lyme disease patients. On the other hand, active immunization studies showed that EF-Tu antibodies did not protect mice from infection when challenged with B. burgdorferi via either needle inoculation or tick bites. Borrelial mouse-tick cycle studies showed that EF-Tu antibodies also did not block B. burgdorferi migration and survival in ticks. Consistent with these findings, we found that EF-Tu primarily localizes in the protoplasmic cylinder of spirochetes and is not on the surface of B. burgdorferi. Taken together, our studies suggest that B. burgdorferi EF-Tu is not surfaced exposed, but it is highly immunogenic and is a potential serodiagnostic marker for Lyme borreliosis.
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25
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Yang X, Lin YP, Heselpoth RD, Buyuktanir O, Qin J, Kung F, Nelson DC, Leong JM, Pal U. Middle region of the Borrelia burgdorferi surface-located protein 1 (Lmp1) interacts with host chondroitin-6-sulfate and independently facilitates infection. Cell Microbiol 2015; 18:97-110. [PMID: 26247174 DOI: 10.1111/cmi.12487] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Revised: 06/23/2015] [Accepted: 07/10/2015] [Indexed: 11/29/2022]
Abstract
Borrelia burgdorferi surface-located membrane protein 1, also known as Lmp1, has been shown to play critical roles in pathogen evasion of host-acquired immune defences, thereby facilitating persistent infection. Lmp1 possesses three regions representing potentially discrete domains: Lmp1N, Lmp1M and Lmp1C. Because of its insignificant homology to known proteins, how Lmp1 or its specific regions contribute to microbial biology and infection remains enigmatic. Here, we show that distinct from Lmp1N and Lmp1C, Lmp1M is composed of at least 70% alpha helices and completely lacks recognizable beta sheets. The region binds to host glycosaminoglycan chondroitin-6-sulfate molecules and facilitates mammalian cell attachment, suggesting an adhesin function of Lmp1M. Phenotypic analysis of the Lmp1-deficient mutant engineered to produce Lmp1M on the microbial surface suggests that Lmp1M can independently support B. burgdorferi infectivity in murine hosts. Further exploration of functions of Lmp1 distinct regions will shed new light on the intriguing biology and infectivity of spirochetes and help develop novel interventions to combat Lyme disease.
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Affiliation(s)
- Xiuli Yang
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD, 20742, USA
| | - Yi-Pin Lin
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA, 02111, USA
| | - Ryan D Heselpoth
- Institute for Bioscience and Biotechnology Research, University of Maryland, 9600 Gudelsky Drive, Rockville, MD, 20850, USA
| | - Ozlem Buyuktanir
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD, 20742, USA
| | - Jinhong Qin
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD, 20742, USA
| | - Faith Kung
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD, 20742, USA
| | - Daniel C Nelson
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD, 20742, USA.,Institute for Bioscience and Biotechnology Research, University of Maryland, 9600 Gudelsky Drive, Rockville, MD, 20850, USA
| | - John M Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA, 02111, USA
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD, 20742, USA
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Kariu T, Sharma K, Singh P, Smith AA, Backstedt B, Buyuktanir O, Pal U. BB0323 and novel virulence determinant BB0238: Borrelia burgdorferi proteins that interact with and stabilize each other and are critical for infectivity. J Infect Dis 2014; 211:462-71. [PMID: 25139020 DOI: 10.1093/infdis/jiu460] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have shown that Borrelia burgdorferi gene product BB0323 is essential for cell fission and pathogen persistence in vivo. Here we describe characterization of a conserved hypothetical protein annotated as BB0238, which specifically interacts with the N-terminal region of BB0323. We show that BB0238 is a subsurface protein, and similar to BB0323, exists in the periplasm and as a membrane-bound protein. Deletion of bb0238 in infectious B. burgdorferi did not affect microbial growth in vitro or survival in ticks, but the mutant was unable to persist in mice or transmit from ticks--defects that are restored on genetic complementation. Remarkably, BB0238 and BB0323 contribute to mutual posttranslational stability, because deletion of one causes dramatic reduction in the protein level of the other partner. Interference with the function of BB0238 or BB0323 and their interaction may provide novel strategies to combat B. burgdorferi infection.
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Affiliation(s)
- Toru Kariu
- Department of Veterinary Medicine and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park
| | - Kavita Sharma
- Department of Veterinary Medicine and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park
| | - Preeti Singh
- Department of Veterinary Medicine and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park
| | - Alexis A Smith
- Department of Veterinary Medicine and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park
| | - Brian Backstedt
- Department of Veterinary Medicine and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park
| | - Ozlem Buyuktanir
- Department of Veterinary Medicine and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park
| | - Utpal Pal
- Department of Veterinary Medicine and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park
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27
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Groshong AM, Blevins JS. Insights into the biology of Borrelia burgdorferi gained through the application of molecular genetics. ADVANCES IN APPLIED MICROBIOLOGY 2014; 86:41-143. [PMID: 24377854 DOI: 10.1016/b978-0-12-800262-9.00002-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Borrelia burgdorferi, the vector-borne bacterium that causes Lyme disease, was first identified in 1982. It is known that much of the pathology associated with Lyme borreliosis is due to the spirochete's ability to infect, colonize, disseminate, and survive within the vertebrate host. Early studies aimed at defining the biological contributions of individual genes during infection and transmission were hindered by the lack of adequate tools and techniques for molecular genetic analysis of the spirochete. The development of genetic manipulation techniques, paired with elucidation and annotation of the B. burgdorferi genome sequence, has led to major advancements in our understanding of the virulence factors and the molecular events associated with Lyme disease. Since the dawn of this genetic era of Lyme research, genes required for vector or host adaptation have garnered significant attention and highlighted the central role that these components play in the enzootic cycle of this pathogen. This chapter covers the progress made in the Borrelia field since the application of mutagenesis techniques and how they have allowed researchers to begin ascribing roles to individual genes. Understanding the complex process of adaptation and survival as the spirochete cycles between the tick vector and vertebrate host will lead to the development of more effective diagnostic tools as well as identification of novel therapeutic and vaccine targets. In this chapter, the Borrelia genes are presented in the context of their general biological roles in global gene regulation, motility, cell processes, immune evasion, and colonization/dissemination.
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Affiliation(s)
- Ashley M Groshong
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Jon S Blevins
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
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Structural modeling and physicochemical characterization provide evidence that P66 forms a β-barrel in the Borrelia burgdorferi outer membrane. J Bacteriol 2013; 196:859-72. [PMID: 24317399 DOI: 10.1128/jb.01236-13] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The Borrelia burgdorferi outer membrane (OM) contains numerous surface-exposed lipoproteins but a relatively low density of integral OM proteins (OMPs). Few membrane-spanning OMPs of B. burgdorferi have been definitively identified, and none are well characterized structurally. Here, we provide evidence that the borrelial OMP P66, a known adhesin with pore-forming activity, forms a β-barrel in the B. burgdorferi OM. Multiple computer-based algorithms predict that P66 forms a β-barrel with either 22 or 24 transmembrane domains. According to our predicted P66 topology, a lysine residue (K487) known to be sensitive to trypsin cleavage is located within a surface-exposed loop. When we aligned the mature P66 amino acid sequences from B. burgdorferi and B. garinii, we found that K487 was present only in the B. burgdorferi P66 protein sequence. When intact cells from each strain were treated with trypsin, only B. burgdorferi P66 was trypsin sensitive, indicating that K487 is surface exposed, as predicted. Consistent with this observation, when we inserted a c-Myc tag adjacent to K487 and utilized surface localization immunofluorescence, we detected the loop containing K487 on the surface of B. burgdorferi. P66 was examined by both Triton X-114 phase partitioning and circular dichroism, confirming that the protein is amphiphilic and contains extensive (48%) β-sheets, respectively. Moreover, P66 also was able to incorporate into liposomes and form channels in large unilamellar vesicles. Finally, blue native PAGE (BN-PAGE) revealed that under nondenaturing conditions, P66 is found in large complexes of ∼400 kDa and ∼600 kDa. Outer surface lipoprotein A (OspA) and OspB both coimmunoprecipitate with P66, demonstrating that P66 associates with OspA and OspB in B. burgdorferi. The combined computer-based structural analyses and supporting physicochemical properties of P66 provide a working model to further examine the porin and integrin-binding activities of this OMP as they relate to B. burgdorferi physiology and Lyme disease pathogenesis.
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Mongodin EF, Casjens SR, Bruno JF, Xu Y, Drabek EF, Riley DR, Cantarel BL, Pagan PE, Hernandez YA, Vargas LC, Dunn JJ, Schutzer SE, Fraser CM, Qiu WG, Luft BJ. Inter- and intra-specific pan-genomes of Borrelia burgdorferi sensu lato: genome stability and adaptive radiation. BMC Genomics 2013; 14:693. [PMID: 24112474 PMCID: PMC3833655 DOI: 10.1186/1471-2164-14-693] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 09/26/2013] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Lyme disease is caused by spirochete bacteria from the Borrelia burgdorferi sensu lato (B. burgdorferi s.l.) species complex. To reconstruct the evolution of B. burgdorferi s.l. and identify the genomic basis of its human virulence, we compared the genomes of 23 B. burgdorferi s.l. isolates from Europe and the United States, including B. burgdorferi sensu stricto (B. burgdorferi s.s., 14 isolates), B. afzelii (2), B. garinii (2), B. "bavariensis" (1), B. spielmanii (1), B. valaisiana (1), B. bissettii (1), and B. "finlandensis" (1). RESULTS Robust B. burgdorferi s.s. and B. burgdorferi s.l. phylogenies were obtained using genome-wide single-nucleotide polymorphisms, despite recombination. Phylogeny-based pan-genome analysis showed that the rate of gene acquisition was higher between species than within species, suggesting adaptive speciation. Strong positive natural selection drives the sequence evolution of lipoproteins, including chromosomally-encoded genes 0102 and 0404, cp26-encoded ospC and b08, and lp54-encoded dbpA, a07, a22, a33, a53, a65. Computer simulations predicted rapid adaptive radiation of genomic groups as population size increases. CONCLUSIONS Intra- and inter-specific pan-genome sizes of B. burgdorferi s.l. expand linearly with phylogenetic diversity. Yet gene-acquisition rates in B. burgdorferi s.l. are among the lowest in bacterial pathogens, resulting in high genome stability and few lineage-specific genes. Genome adaptation of B. burgdorferi s.l. is driven predominantly by copy-number and sequence variations of lipoprotein genes. New genomic groups are likely to emerge if the current trend of B. burgdorferi s.l. population expansion continues.
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Affiliation(s)
- Emmanuel F Mongodin
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
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30
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Yang X, Hegde S, Shroder DY, Smith AA, Promnares K, Neelakanta G, Anderson JF, Fikrig E, Pal U. The lipoprotein La7 contributes to Borrelia burgdorferi persistence in ticks and their transmission to naïve hosts. Microbes Infect 2013; 15:729-37. [PMID: 23774694 PMCID: PMC3769513 DOI: 10.1016/j.micinf.2013.06.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 03/25/2013] [Accepted: 06/01/2013] [Indexed: 11/30/2022]
Abstract
La7, an immunogenic outer membrane lipoprotein of Borrelia burgdorferi, produced during infection, has been shown to play a redundant role in mammalian infectivity. Here we show that La7 facilitates pathogen survival in all tested phases of the vector-specific spirochete life cycle, including tick-to-host transmission. Unlike wild type or la7-complemented isolates, isogenic La7-deficient spirochetes are severely impaired in their ability to persist within feeding ticks during acquisition from mice, in quiescent ticks during larval-nymphal inter-molt, and in subsequent pathogen transmission from ticks to naïve hosts. Analysis of gene expression during the major stages of the tick-rodent infection cycle showed increased expression of la7 in the vector and a swift downregulation in the mammalian hosts. Co-immunoprecipitation studies coupled with liquid chromatography-mass spectrometry analysis further suggested that La7, a highly conserved and abundant inner membrane protein, is involved in protein-protein interaction with a discrete set of borrelial ligands although biological significance of such interactions remains unclear. Further characterization of vector-induced membrane antigens like La7 and its interacting partners will likely aid in our understanding of the molecular details of B. burgdorferi persistence and transmission through a complex enzootic cycle.
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Affiliation(s)
- Xiuli Yang
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland 20742, USA
| | - Shylaja Hegde
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland 20742, USA
| | - Deborah Y. Shroder
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland 20742, USA
| | - Alexis A. Smith
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland 20742, USA
| | - Kamoltip Promnares
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland 20742, USA
| | - Girish Neelakanta
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, 06511, USA
| | - John F. Anderson
- Department of Entomology and Center for Vector Biology and Zoonotic Diseases, Connecticut Agricultural Experiment Station, New Haven, 06504
| | - Erol Fikrig
- Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, 06511, USA
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland 20742, USA
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31
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Coburn J, Leong J, Chaconas G. Illuminating the roles of the Borrelia burgdorferi adhesins. Trends Microbiol 2013; 21:372-9. [PMID: 23876218 DOI: 10.1016/j.tim.2013.06.005] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 06/13/2013] [Accepted: 06/14/2013] [Indexed: 01/13/2023]
Abstract
The Lyme disease spirochetes, Borrelia burgdorferi (sensu lato), must cause persistent, disseminated infection to be maintained in the natural enzootic cycle. In human Lyme disease, spirochetes spread from the site of a tick bite to colonize multiple tissue sites, causing multisystem clinical manifestations. The Lyme spirochetes produce many adhesive surface proteins that collectively recognize diverse host substrates and cell types and are likely to promote dissemination and chronic infection in a variety of tissues. Recent application of state-of-the-art in vivo imaging technologies is illuminating mechanisms of interaction of B. burgdorferi with the host and the importance of multiple adhesins during mammalian infection.
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Affiliation(s)
- Jenifer Coburn
- Division of Infectious Diseases, Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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32
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Kariu T, Yang X, Marks CB, Zhang X, Pal U. Proteolysis of BB0323 results in two polypeptides that impact physiologic and infectious phenotypes in Borrelia burgdorferi. Mol Microbiol 2013; 88:510-22. [PMID: 23489252 DOI: 10.1111/mmi.12202] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2013] [Indexed: 01/12/2023]
Abstract
Borrelia burgdorferi gene product BB0323 is required for cell fission and pathogen persistence in vivo. Here, we show that BB0323, which is conserved among globally prevalent infectious strains, supports normal spirochaete growth and morphology even at early phases of cell division. We demonstrate that native BB0323 undergoes proteolytic processing at the C-terminus, at a site after the first 202 N-terminal amino acids. We further identified a periplasmic BB0323 binding protein in B. burgdorferi, annotated as BB0104, having serine protease activity responsible for the primary cleavage of BB0323 to produce discrete N- and C-terminal polypeptides. These two BB0323 polypeptides interact with each other, and either individually or as a complex, are associated with multiple functions in spirochaete biology and infectivity. While N-terminal BB0323 is adequate to support cell fission, the C-terminal LysM domain is dispensable for this process, despite its ability to bind B. burgdorferi peptidoglycan. However, the LysM domain or the precisely processed BB0323 product is essential for mammalian infection. As BB0323 is a membrane protein crucial for B. burgdorferi survival in vivo, exploring its function may suggest novel ways to interrupt infection while enhancing our understanding of the intricate spirochaete fission process.
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Affiliation(s)
- Toru Kariu
- Department of Veterinary Medicine and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA
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33
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Yang X, Qin J, Promnares K, Kariu T, Anderson JF, Pal U. Novel microbial virulence factor triggers murine lyme arthritis. J Infect Dis 2013; 207:907-18. [PMID: 23303811 DOI: 10.1093/infdis/jis930] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Borrelia burgdorferi bba57 is a conserved gene encoding a potential lipoprotein of unknown function. Here we show that bba57 is up-regulated in vivo and is required for early murine infection and potential spirochete transmission process. Although BBA57 is dispensable for late murine infection, the mutants were unable to induce disease. We show that BBA57, an outer membrane and surface-exposed antigen, is a major trigger of murine Lyme arthritis; even in cases of larger challenge inocula, which allow their persistence in joints at a level similar to wild-type spirochetes, bba57 mutants are unable to induce joint inflammation. We further showed that BBA57 deficiency reduces the expression of selected "neutrophil-recruiting" chemokines and associated receptors, causing significant impairment of neutrophil chemotaxis. New approaches to combat Lyme disease may include strategies to interfere with BBA57, a novel virulence factor and a trigger of murine Lyme arthritis.
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Affiliation(s)
- Xiuli Yang
- Department of Veterinary Medicine, University of Maryland, College Park and Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD, USA
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34
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Chan K, Awan M, Barthold SW, Parveen N. Comparative molecular analyses of Borrelia burgdorferi sensu stricto strains B31 and N40D10/E9 and determination of their pathogenicity. BMC Microbiol 2012; 12:157. [PMID: 22846633 PMCID: PMC3511255 DOI: 10.1186/1471-2180-12-157] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 06/11/2012] [Indexed: 11/24/2022] Open
Abstract
Background Lyme disease in the United States is caused primarily by B. burgdorferi sensu stricto while other species are also prevalent in Europe. Genetic techniques have identified several chromosomal and plasmid-borne regulatory and virulence factors involved in Lyme pathogenesis. B31 and N40 are two widely studied strains of B. burgdorferi, which belong to two different 16 S-23 S rRNA spacer types (RST) and outer surface protein C (OspC) allelic groups. However, the presence of several known virulence factors in N40 has not been investigated. This is the first comprehensive study that compared these two strains both in vitro and using the mouse model of infection. Results Phylogenetic analyses predict B31 to be more infectious. However, our studies here indicate that N40D10/E9 is more infectious than the B31 strain at lower doses of inoculation in the susceptible C3H mice. Based-upon a careful analyses of known adhesins of these strains, it is predicted that the absence of a known fibronectin-glycosaminoglycan binding adhesin, bbk32, in the N40 strain could at least partially be responsible for reduction in its binding to Vero cells in vitro. Nevertheless, this difference does not affect the infectivity of N40D10/E9 strain. The genes encoding known regulatory and virulence factors critical for pathogenesis were detected in both strains. Differences in the protein profiles of these B. burgdorferi strains in vitro suggest that the novel, differentially expressed molecules may affect infectivity of B. burgdorferi. Further exacerbation of these molecular differences in vivo could affect the pathogenesis of spirochete strains. Conclusion Based upon the studies here, it can be predicted that N40D10/E9 disseminated infection at lower doses may be enhanced by its lower binding to epithelial cells at the site of inoculation due to the absence of BBK32. We suggest that complete molecular analyses of virulence factors followed by their evaluation using the mouse infection model should form the basis of determining infectivity and pathogenicity of different strains rather than simple phylogenetic group analyses. This study further emphasizes a need to investigate multiple invasive strains of B. burgdorferi to fully appreciate the pathogenic mechanisms that contribute to Lyme disease manifestations.
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Affiliation(s)
- Kamfai Chan
- Department of Microbiology and Molecular Genetics, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, 225 Warren Street, Newark, NJ 07103-3535, USA
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35
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Kenedy MR, Lenhart TR, Akins DR. The role of Borrelia burgdorferi outer surface proteins. ACTA ACUST UNITED AC 2012; 66:1-19. [PMID: 22540535 DOI: 10.1111/j.1574-695x.2012.00980.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 04/13/2012] [Accepted: 04/25/2012] [Indexed: 12/18/2022]
Abstract
Human pathogenic spirochetes causing Lyme disease belong to the Borrelia burgdorferi sensu lato complex. Borrelia burgdorferi organisms are extracellular pathogens transmitted to humans through the bite of Ixodes spp. ticks. These spirochetes are unique in that they can cause chronic infection and persist in the infected human, even though a robust humoral and cellular immune response is produced by the infected host. How this extracellular pathogen is able to evade the host immune response for such long periods of time is currently unclear. To gain a better understanding of how this organism persists in the infected human, many laboratories have focused on identifying and characterizing outer surface proteins of B. burgdorferi. As the interface between B. burgdorferi and its human host is its outer surface, proteins localized to the outer membrane must play an important role in dissemination, virulence, tissue tropism, and immune evasion. Over the last two decades, numerous outer surface proteins from B. burgdorferi have been identified, and more recent studies have begun to elucidate the functional role(s) of many borrelial outer surface proteins. This review summarizes the outer surface proteins identified in B. burgdorferi to date and provides detailed insight into the functions of many of these proteins as they relate to the unique parasitic strategy of this spirochetal pathogen.
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Affiliation(s)
- Melisha R Kenedy
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, USA
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36
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A surface enolase participates in Borrelia burgdorferi-plasminogen interaction and contributes to pathogen survival within feeding ticks. Infect Immun 2011; 80:82-90. [PMID: 22025510 DOI: 10.1128/iai.05671-11] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Borrelia burgdorferi, a tick-borne bacterial pathogen, causes a disseminated infection involving multiple organs known as Lyme disease. Surface proteins can directly participate in microbial virulence by facilitating pathogen dissemination via interaction with host factors. We show here that a fraction of the B. burgdorferi chromosomal gene product BB0337, annotated as enolase or phosphopyruvate dehydratase, is associated with spirochete outer membrane and is surface exposed. B. burgdorferi enolase, either in a recombinant form or as a membrane-bound native antigen, displays enzymatic activities intrinsic to the glycolytic pathway. However, the protein also interacts with host plasminogen, potentially leading to its activation and resulting in B. burgdorferi-induced fibrinolysis. As expected, enolase displayed consistent expression in vivo, however, with a variable temporal and spatial expression during spirochete infection in mice and ticks. Despite an extracellular exposure of the antigen and a potential role in host-pathogen interaction, active immunization of mice with recombinant enolase failed to evoke protective immunity against subsequent B. burgdorferi infection. In contrast, enolase immunization of murine hosts significantly reduced the acquisition of spirochetes by feeding ticks, suggesting that the protein could have a stage-specific role in B. burgdorferi survival in the feeding vector. Strategies to interfere with the function of surface enolase could contribute to the development of novel preventive measures to interrupt the spirochete infection cycle and reduce the incidences of Lyme disease.
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37
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Kumar M, Kaur S, Kariu T, Yang X, Bossis I, Anderson JF, Pal U. Borrelia burgdorferi BBA52 is a potential target for transmission blocking Lyme disease vaccine. Vaccine 2011; 29:9012-9. [PMID: 21945261 DOI: 10.1016/j.vaccine.2011.09.035] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 09/08/2011] [Accepted: 09/09/2011] [Indexed: 11/19/2022]
Abstract
The surface-exposed antigens of Borrelia burgdorferi represent important targets for induction of protective host immune responses. BBA52 is preferentially expressed by B. burgdorferi in the feeding tick, and a targeted deletion of bba52 interferes with vector-host transitions in vivo. In this study, we demonstrate that BBA52 is an outer membrane surface-exposed protein and that disulfide bridges take part in the homo-oligomeric assembly of native protein. BBA52 antibodies lack detectable borreliacidal activities in vitro. However, active immunization studies demonstrated that BBA52 vaccinated mice were significantly less susceptible to subsequent tick-borne challenge infection. Similarly, passive transfer of BBA52 antibodies in ticks completely blocked B. burgdorferi transmission from feeding ticks to naïve mice. Taken together, these studies highlight the role of BBA52 in spirochete dissemination from ticks to mice and demonstrate the potential of BBA52 antibody-mediated strategy to complement the ongoing efforts to develop vaccines for blocking the transmission of B. burgdorferi.
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Affiliation(s)
- Manish Kumar
- Department of Veterinary Medicine, University of Maryland and Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD 20742, United States
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