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Satola SW, Schechter MC, Wilde S, Stephens DS. Host Defenses to Extracellular Bacteria Including Spirochetes. Clin Immunol 2023. [DOI: 10.1016/b978-0-7020-8165-1.00027-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
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Kubelkova K, Macela A. Francisella and Antibodies. Microorganisms 2021; 9:microorganisms9102136. [PMID: 34683457 PMCID: PMC8538966 DOI: 10.3390/microorganisms9102136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 01/17/2023] Open
Abstract
Immune responses to intracellular pathogens depend largely upon the activation of T helper type 1-dependent mechanisms. The contribution of B cells to establishing protective immunity has long been underestimated. Francisella tularensis, including a number of subspecies, provides a suitable model for the study of immune responses against intracellular bacterial pathogens. We previously demonstrated that Francisella infects B cells and activates B-cell subtypes to produce a number of cytokines and express the activation markers. Recently, we documented the early production of natural antibodies as a consequence of Francisella infection in mice. Here, we summarize current knowledge on the innate and acquired humoral immune responses initiated by Francisella infection and their relationships with the immune defense systems.
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Navasa N, Fikrig E, Anguita J. Host Defenses to Spirochetes. Clin Immunol 2019. [DOI: 10.1016/b978-0-7020-6896-6.00028-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Bencurova E, Gupta SK, Oskoueian E, Bhide M, Dandekar T. Omics and bioinformatics applied to vaccine development against Borrelia. Mol Omics 2018; 14:330-340. [PMID: 30113617 DOI: 10.1039/c8mo00130h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Borrelia burgdorferi is an extracellular spirochete that causes Lyme disease. Currently, no effective vaccine is available for humans and animals except for dogs. In the present study, an extensive bioinformatics pipeline was established to predict new candidates that can be used for vaccine development including building the protein-protein interaction network based on orthologues of experimentally verified protein-protein interaction networks, elucidation of the proteins involved in the immune response, selection of the topologically-interesting proteins and their prioritization based on their antigenicity. Proteomic network analysis yielded an interactome network with 120 nodes with 97 interactions. Proteins were selected to obtain a subnet containing only the borrelial membrane proteins and immune-related host proteins. This strategy resulted in the selection of 15 borrelial targets, which were subjected to extensive bioinformatics analysis to predict their antigenic properties. Based on the strategy applied in this study the proteins encoded by erpX (ErpX proteins, UniProt ID: H7C7L6), erpL (ErpL protein, UniProt ID: H7C7M3) and erpY (ErpY protein, UniProt ID: Q9S0D9) are suggested as a novel set of vaccine targets to control Lyme disease. Moreover, five different tools were used to validate their antigenicity regarding B-cells. The combination of all these proteins in a vaccine should allow improved protection against Borrelia infection.
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Affiliation(s)
- Elena Bencurova
- Department of Bioinformatics, Biocenter, Am Hubland, D-97074 Wuerzburg, Germany.
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Brock SR, Parmely MJ. Francisella tularensis Confronts the Complement System. Front Cell Infect Microbiol 2017; 7:523. [PMID: 29312899 PMCID: PMC5742141 DOI: 10.3389/fcimb.2017.00523] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 12/08/2017] [Indexed: 12/30/2022] Open
Abstract
Francisella tularensis has developed a number of effective evasion strategies to counteract host immune defenses, not the least of which is its ability to interact with the complement system to its own advantage. Following exposure of the bacterium to fresh human serum, complement is activated and C3b and iC3b can be found covalently attached to the bacterial surface. However, the lipopolysaccharide and capsule of the F. tularensis cell wall prevent complement-mediated lysis and endow the bacterium with serum resistance. Opsonization of F. tularensis with C3 greatly increases its uptake by human neutrophils, dendritic cells and macrophages. Uptake occurs by an unusual looping morphology in human macrophages. Complement receptor 3 is thought to play an important role in opsonophagocytosis by human macrophages, and signaling through this receptor can antagonize Toll-like receptor 2-initiated macrophage activation. Complement C3 also determines the survival of infected human macrophages and perhaps other cell types. C3-opsonization of F. tularensis subsp. tularensis strain SCHU S4 results in greatly increased death of infected human macrophages, which requires more than complement receptor engagement and is independent of the intracellular replication by the pathogen. Given its entry into the cytosol of host cells, F. tularensis has the potential for a number of other complement-mediated interactions. Studies on the uptake C3-opsonized adenovirus have suggested the existence of a C3 sensing system that initiates cellular responses to cytosolic C3b present on invading microbes. Here we propose that C3 peptides enter the cytosol of human macrophages following phagosome escape of F. tularensis and are recognized as intruding molecular patterns that signal host cell death. With the discovery of new roles for intracellular C3, a better understanding of tularemia pathogenesis is likely to emerge.
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Affiliation(s)
- Susan R Brock
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Michael J Parmely
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS, United States
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Bayly-Jones C, Bubeck D, Dunstone MA. The mystery behind membrane insertion: a review of the complement membrane attack complex. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160221. [PMID: 28630159 PMCID: PMC5483522 DOI: 10.1098/rstb.2016.0221] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2016] [Indexed: 12/14/2022] Open
Abstract
The membrane attack complex (MAC) is an important innate immune effector of the complement terminal pathway that forms cytotoxic pores on the surface of microbes. Despite many years of research, MAC structure and mechanism of action have remained elusive, relying heavily on modelling and inference from biochemical experiments. Recent advances in structural biology, specifically cryo-electron microscopy, have provided new insights into the molecular mechanism of MAC assembly. Its unique 'split-washer' shape, coupled with an irregular giant β-barrel architecture, enable an atypical mechanism of hole punching and represent a novel system for which to study pore formation. This review will introduce the complement terminal pathway that leads to formation of the MAC. Moreover, it will discuss how structures of the pore and component proteins underpin a mechanism for MAC function, modulation and inhibition.This article is part of the themed issue 'Membrane pores: from structure and assembly, to medicine and technology'.
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Affiliation(s)
- Charles Bayly-Jones
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton Campus, Melbourne, Victoria 3800, Australia
- ARC Centre of Excellence in Advanced Molecular Imaging, Biomedicine Discovery Institute, Monash University, Clayton Campus, Melbourne, Victoria 3800, Australia
| | - Doryen Bubeck
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW2 7AZ, UK
| | - Michelle A Dunstone
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton Campus, Melbourne, Victoria 3800, Australia
- ARC Centre of Excellence in Advanced Molecular Imaging, Biomedicine Discovery Institute, Monash University, Clayton Campus, Melbourne, Victoria 3800, Australia
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Stone BL, Brissette CA. Host Immune Evasion by Lyme and Relapsing Fever Borreliae: Findings to Lead Future Studies for Borrelia miyamotoi. Front Immunol 2017; 8:12. [PMID: 28154563 PMCID: PMC5243832 DOI: 10.3389/fimmu.2017.00012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 01/05/2017] [Indexed: 12/13/2022] Open
Abstract
The emerging pathogen, Borrelia miyamotoi, is a relapsing fever spirochete vectored by the same species of Ixodes ticks that carry the causative agents of Lyme disease in the US, Europe, and Asia. Symptoms caused by infection with B. miyamotoi are similar to a relapsing fever infection. However, B. miyamotoi has adapted to different vectors and reservoirs, which could result in unique physiology, including immune evasion mechanisms. Lyme Borrelia utilize a combination of Ixodes-produced inhibitors and native proteins [i.e., factor H-binding proteins (FHBPs)/complement regulator-acquiring surface proteins, p43, BBK32, BGA66, BGA71, CD59-like protein] to inhibit complement, while some relapsing fever spirochetes use C4b-binding protein and likely Ornithodoros-produced inhibitors. To evade the humoral response, Borrelia utilize antigenic variation of either outer surface proteins (Osps) and the Vmp-like sequences (Vls) system (Lyme borreliae) or variable membrane proteins (Vmps, relapsing fever borreliae). B. miyamotoi possesses putative FHBPs and antigenic variation of Vmps has been demonstrated. This review summarizes and compares the common mechanisms utilized by Lyme and relapsing fever spirochetes, as well as the current state of understanding immune evasion by B. miyamotoi.
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Affiliation(s)
- Brandee L Stone
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota , Grand Forks, ND , USA
| | - Catherine A Brissette
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota , Grand Forks, ND , USA
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Hovingh ES, van den Broek B, Jongerius I. Hijacking Complement Regulatory Proteins for Bacterial Immune Evasion. Front Microbiol 2016; 7:2004. [PMID: 28066340 PMCID: PMC5167704 DOI: 10.3389/fmicb.2016.02004] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 11/30/2016] [Indexed: 12/11/2022] Open
Abstract
The human complement system plays an important role in the defense against invading pathogens, inflammation and homeostasis. Invading microbes, such as bacteria, directly activate the complement system resulting in the formation of chemoattractants and in effective labeling of the bacteria for phagocytosis. In addition, formation of the membrane attack complex is responsible for direct killing of Gram-negative bacteria. In turn, bacteria have evolved several ways to evade complement activation on their surface in order to be able to colonize and invade the human host. One important mechanism of bacterial escape is attraction of complement regulatory proteins to the microbial surface. These molecules are present in the human body for tight regulation of the complement system to prevent damage to host self-surfaces. Therefore, recruitment of complement regulatory proteins to the bacterial surface results in decreased complement activation on the microbial surface which favors bacterial survival. This review will discuss recent advances in understanding the binding of complement regulatory proteins to the bacterial surface at the molecular level. This includes, new insights that have become available concerning specific conserved motives on complement regulatory proteins that are favorable for microbial binding. Finally, complement evasion molecules are of high importance for vaccine development due to their dominant role in bacterial survival, high immunogenicity and homology as well as their presence on the bacterial surface. Here, the use of complement evasion molecules for vaccine development will be discussed.
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Affiliation(s)
- Elise S. Hovingh
- Department of Medical Microbiology, University Medical Center UtrechtUtrecht, Netherlands
- Centre for Infectious Disease Control, National Institute for Public Health and the EnvironmentBilthoven, Netherlands
| | - Bryan van den Broek
- Department of Medical Microbiology, University Medical Center UtrechtUtrecht, Netherlands
| | - Ilse Jongerius
- Department of Medical Microbiology, University Medical Center UtrechtUtrecht, Netherlands
- Centre for Infectious Disease Control, National Institute for Public Health and the EnvironmentBilthoven, Netherlands
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Travelling between Two Worlds: Complement as a Gatekeeper for an Expanded Host Range of Lyme Disease Spirochetes. Vet Sci 2016; 3:vetsci3020012. [PMID: 29056721 PMCID: PMC5644625 DOI: 10.3390/vetsci3020012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 06/03/2016] [Accepted: 06/06/2016] [Indexed: 01/21/2023] Open
Abstract
Evading innate immunity is a prerequisite for pathogenic microorganisms in order to survive in their respective hosts. Concerning Lyme disease spirochetes belonging to the Borrelia (B.) burgdorferi sensu lato group, a broad range of diverse vertebrates serve as reservoir or even as incidental hosts, including humans. The capability to infect multiple hosts implies that spirochetes have developed sophisticated means to counter the destructive effects of complement of humans and various animals. While the means by which spirochetes overcome the hosts immune defense are far from being completely understood, there is a growing body of evidence suggesting that binding of the key regulator of the alternative pathway, Factor H, plays a pivotal role for immune evasion and that Factor H is an important determinant of host specificity. This review covers (i) the contribution of complement in host-specificity and transmissibility of Lyme disease spirochetes; (ii) the involvement of borrelial-derived determinants to host specificity; (iii) the interplay of human and animal Factor H with complement-acquiring surface proteins of diverse borrelial species; and (iv) the potential role of additional animal complement proteins in the immune evasion of spirochetes.
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