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Alakavuklar MA, Fiebig A, Crosson S. The Brucella Cell Envelope. Annu Rev Microbiol 2023; 77:233-253. [PMID: 37104660 PMCID: PMC10787603 DOI: 10.1146/annurev-micro-032521-013159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
The cell envelope is a multilayered structure that insulates the interior of bacterial cells from an often chaotic outside world. Common features define the envelope across the bacterial kingdom, but the molecular mechanisms by which cells build and regulate this critical barrier are diverse and reflect the evolutionary histories of bacterial lineages. Intracellular pathogens of the genus Brucella exhibit marked differences in cell envelope structure, regulation, and biogenesis when compared to more commonly studied gram-negative bacteria and therefore provide an excellent comparative model for study of the gram-negative envelope. We review distinct features of the Brucella envelope, highlighting a conserved regulatory system that links cell cycle progression to envelope biogenesis and cell division. We further discuss recently discovered structural features of the Brucella envelope that ensure envelope integrity and that facilitate cell survival in the face of host immune stressors.
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Affiliation(s)
- Melene A Alakavuklar
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA;
| | - Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA;
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA;
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2
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Hao M, Wang M, Zhao D, Shi Y, Yuan Y, Li J, Zhai Y, Liu X, Zhou D, Chen H, Lin P, Tang K, Liu W, Jin Y, Wang A. Alr Gene in Brucella suis S2: Its Role in Lipopolysaccharide Biosynthesis and Bacterial Virulence in RAW264.7. Int J Mol Sci 2023; 24:10744. [PMID: 37445922 DOI: 10.3390/ijms241310744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 06/24/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
Brucella suis, the causative agent of brucellosis, poses a significant public health and animal husbandry threat. However, the role of the alanine racemase (alr) gene, which encodes alanine racemase in Brucella, remains unclear. Here, we analyzed an alr deletion mutant and a complemented strain of Brucella suis S2. The knockout strain displayed an unaltered, smooth phenotype in acriflavine agglutination tests but lacked the core polysaccharide portion of lipopolysaccharide (LPS). Genes involved in the LPS synthesis were significantly upregulated in the deletion mutant. The alr deletion strain exhibited reduced intracellular viability in the macrophages, increased macrophage-mediated killing, and upregulation of the apoptosis markers. Bcl2, an anti-apoptotic protein, was downregulated, while the pro-apoptotic proteins, Bax, Caspase-9, and Caspase-3, were upregulated in the macrophages infected with the deletion strain. The infected macrophages showed increased mitochondrial membrane permeability, Cytochrome C release, and reactive oxygen species, activating the mitochondrial apoptosis pathway. These findings revealed that alanine racemase was dispensable in B. suis S2 but influenced the strain's rough features and triggered the mitochondrial apoptosis pathway during macrophage invasion. The deletion of the alr gene reduced the intracellular survival and virulence. This study enhances our understanding of the molecular mechanism underlying Brucella's survival and virulence and, specifically, how alr gene affects host immune evasion by regulating bacterial LPS biosynthesis.
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Affiliation(s)
- Mingyue Hao
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Minghui Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Danyu Zhao
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Yong Shi
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Ye Yuan
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Junmei Li
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Yunyi Zhai
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Xiaofang Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Dong Zhou
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Huatao Chen
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Pengfei Lin
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Keqiong Tang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Wei Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Yaping Jin
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
| | - Aihua Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling District, Xianyang 712100, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture, Northwest A&F University, Yangling District, Xianyang 712100, China
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Touloudi A, McGiven J, Cawthraw S, Valiakos G, Kostoulas P, Duncombe L, Gortázar C, Boadella M, Sofia M, Athanasakopoulou Z, Chatzopoulos DC, Spyrou V, Petrovska L, Billinis C. Development of a Multiplex Bead Assay to Detect Serological Responses to Brucella Species in Domestic Pigs and Wild Boar with the Potential to Overcome Cross-Reactivity with Yersinia enterocolitica O:9. Microorganisms 2022; 10:microorganisms10071362. [PMID: 35889081 PMCID: PMC9324436 DOI: 10.3390/microorganisms10071362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 11/16/2022] Open
Abstract
The aim of this study was to develop a multiplex bead assay using a Brucella rLPS antigen, a Brucella suis smooth antigen, and a Yersinia enterocolitica O:9 antigen that not only discriminates Brucella-infected from Brucella-uninfected pigs and wild boar, but also overcomes the cross reactivity with Y. enterocolitica O:9. Sera from 126 domestic pigs were tested: 29 pigs were Brucella infected, 80 were non-infected and 17 were confirmed to be false positive serological reactors (FPSR). Sera from 49 wild boar were tested: 18 were positive and 31 were negative. Using the rLPS antigen, 26/29 Brucella-infected domestic pigs and 15/18 seropositive wild boar were positive, while 75/80 non-Brucella infected domestic pigs, all FPSR, and all seronegative wild boar were negative. Using the smooth B. suis 1330 antigen, all Brucella-infected domestic pigs, 9/17 FPSR and all seropositive wild boar were positive, while all non-infected pigs and 30/31 seronegative wild boar were negative. The ratio of the readouts from the smooth B. suis antigen and Y. enterocolitica O:9 antigen enabled discriminating all Brucella infected individuals from the FPSR domestic pigs. These results demonstrate the potential of this assay for use in the surveillance of brucellosis, overcoming the cross-reactivity with Y. enterocolitica.
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Affiliation(s)
- Antonia Touloudi
- Faculty of Veterinary Science, University of Thessaly, 431 00 Karditsa, Greece; (A.T.); (G.V.); (M.S.); (Z.A.)
| | - John McGiven
- Department of Bacteriology, Animal and Plant Health Agency, OIE/FAO Brucellosis Reference Laboratory, Woodham Lane, Addlestone, Surrey KT15 3NB, UK; (J.M.); (S.C.); (L.D.)
| | - Shaun Cawthraw
- Department of Bacteriology, Animal and Plant Health Agency, OIE/FAO Brucellosis Reference Laboratory, Woodham Lane, Addlestone, Surrey KT15 3NB, UK; (J.M.); (S.C.); (L.D.)
| | - George Valiakos
- Faculty of Veterinary Science, University of Thessaly, 431 00 Karditsa, Greece; (A.T.); (G.V.); (M.S.); (Z.A.)
| | - Polychronis Kostoulas
- Faculty of Public and One Health, University of Thessaly, 431 00 Karditsa, Greece; (P.K.); (D.C.C.)
| | - Lucy Duncombe
- Department of Bacteriology, Animal and Plant Health Agency, OIE/FAO Brucellosis Reference Laboratory, Woodham Lane, Addlestone, Surrey KT15 3NB, UK; (J.M.); (S.C.); (L.D.)
| | - Christian Gortázar
- SaBio, Instituto de Investigación en Recursos Cinegéticos IREC, 13005 Ciudad Real, Spain;
| | | | - Marina Sofia
- Faculty of Veterinary Science, University of Thessaly, 431 00 Karditsa, Greece; (A.T.); (G.V.); (M.S.); (Z.A.)
| | - Zoi Athanasakopoulou
- Faculty of Veterinary Science, University of Thessaly, 431 00 Karditsa, Greece; (A.T.); (G.V.); (M.S.); (Z.A.)
| | - Dimitris C. Chatzopoulos
- Faculty of Public and One Health, University of Thessaly, 431 00 Karditsa, Greece; (P.K.); (D.C.C.)
| | - Vassiliki Spyrou
- Faculty of Animal Science, University of Thessaly, 412 22 Larissa, Greece;
| | - Liljana Petrovska
- Department of Bacteriology, Animal and Plant Health Agency, OIE/FAO Brucellosis Reference Laboratory, Woodham Lane, Addlestone, Surrey KT15 3NB, UK; (J.M.); (S.C.); (L.D.)
- Correspondence: (L.P.); (C.B.)
| | - Charalambos Billinis
- Faculty of Veterinary Science, University of Thessaly, 431 00 Karditsa, Greece; (A.T.); (G.V.); (M.S.); (Z.A.)
- Faculty of Public and One Health, University of Thessaly, 431 00 Karditsa, Greece; (P.K.); (D.C.C.)
- Correspondence: (L.P.); (C.B.)
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The Tip of Brucella O-Polysaccharide Is a Potent Epitope in Response to Brucellosis Infection and Enables Short Synthetic Antigens to Be Superior Diagnostic Reagents. Microorganisms 2022; 10:microorganisms10040708. [PMID: 35456759 PMCID: PMC9024974 DOI: 10.3390/microorganisms10040708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/09/2022] [Accepted: 03/11/2022] [Indexed: 12/10/2022] Open
Abstract
Brucellosis is a global disease and the world’s most prevalent zoonosis. All cases in livestock and most cases in humans are caused by members of the genus Brucella that possess a surface O-polysaccharide (OPS) comprised of a rare monosaccharide 4-deoxy-4-formamido-D-mannopyranose assembled with α1,2 and α1,3 linkages. The OPS of the bacterium is the basis for serodiagnostic tests for brucellosis. Bacteria that also contain the same rare monosaccharide can induce antibodies that cross-react in serological tests. In previous work we established that synthetic oligosaccharides, representing elements of the Brucella A and M polysaccharide structures, were excellent antigens to explore the antibody response in the context of infection, immunisation and cross reaction. These studies suggested the existence of antibodies that are specific to the tip of the Brucella OPS. Sera from naturally and experimentally Brucella abortus-infected cattle as well as from cattle experimentally infected with the cross-reactive bacterium Yersinia enterocolitica O:9 and field sera that cross react in conventional serological assays were studied here with an expanded panel of synthetic antigens. The addition of chemical features to synthetic antigens that block antibody binding to the tip of the OPS dramatically reduced their polyclonal antibody binding capability providing conclusive evidence that the OPS tip (non-reducing end) is a potent epitope. Selected short oligosaccharides, including those that were exclusively α1,2 linked, also demonstrated superior specificity when evaluated with cross reactive sera compared to native smooth lipopolysaccharide (sLPS) antigen and capped native OPS. This surprising discovery suggests that the OPS tip epitope, even though common to both Brucella and Y. enterocolitica O:9, has more specific diagnostic properties than the linear portion of the native antigens. This finding opens the way to the development of improved serological tests for brucellosis.
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Stranahan LW, Arenas-Gamboa AM. When the Going Gets Rough: The Significance of Brucella Lipopolysaccharide Phenotype in Host-Pathogen Interactions. Front Microbiol 2021; 12:713157. [PMID: 34335551 PMCID: PMC8319746 DOI: 10.3389/fmicb.2021.713157] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/22/2021] [Indexed: 01/18/2023] Open
Abstract
Brucella is a facultatively intracellular bacterial pathogen and the cause of worldwide zoonotic infections, infamous for its ability to evade the immune system and persist chronically within host cells. Despite the frequent association with attenuation in other Gram-negative bacteria, a rough lipopolysaccharide phenotype is retained by Brucella canis and Brucella ovis, which remain fully virulent in their natural canine and ovine hosts, respectively. While these natural rough strains lack the O-polysaccharide they, like their smooth counterparts, are able to evade and manipulate the host immune system by exhibiting low endotoxic activity, resisting destruction by complement and antimicrobial peptides, entering and trafficking within host cells along a similar pathway, and interfering with MHC-II antigen presentation. B. canis and B. ovis appear to have compensated for their roughness by alterations to their outer membrane, especially in regards to outer membrane proteins. B. canis, in particular, also shows evidence of being less proinflammatory in vivo, suggesting that the rough phenotype may be associated with an enhanced level of stealth that could allow these pathogens to persist for longer periods of time undetected. Nevertheless, much additional work is required to understand the correlates of immune protection against the natural rough Brucella spp., a critical step toward development of much-needed vaccines. This review will highlight the significance of rough lipopolysaccharide in the context of both natural disease and host–pathogen interactions with an emphasis on natural rough Brucella spp. and the implications for vaccine development.
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Affiliation(s)
- Lauren W Stranahan
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States
| | - Angela M Arenas-Gamboa
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States
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6
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Abstract
Brucellosis is a bacterial disease of domestic animals and humans. The pathogenic ability of Brucella organisms relies on their stealthy strategy and their capacity to replicate within host cells and to induce long-lasting infections. Brucella organisms barely induce neutrophil activation and survive within these leukocytes by resisting microbicidal mechanisms. Very few Brucella-infected neutrophils are found in the target organs, except for the bone marrow, early in infection. Still, Brucella induces a mild reactive oxygen species formation and, through its lipopolysaccharide, promotes the premature death of neutrophils, which release chemokines and express "eat me" signals. This effect drives the phagocytosis of infected neutrophils by mononuclear cells that become thoroughly susceptible to Brucella replication and vehicles for bacterial dispersion. The premature death of the infected neutrophils proceeds without NETosis, necrosis/oncosis, or classical apoptosis morphology. In the absence of neutrophils, the Th1 response exacerbates and promotes bacterial removal, indicating that Brucella-infected neutrophils dampen adaptive immunity. This modulatory effect opens a window for bacterial dispersion in host tissues before adaptive immunity becomes fully activated. However, the hyperactivation of immunity is not without a price, since neutropenic Brucella-infected animals develop cachexia in the early phases of the disease. The delay in the immunological response seems a sine qua non requirement for the development of long-lasting brucellosis. This property may be shared with other pathogenic alphaproteobacteria closely related to Brucella We propose a model in which Brucella-infected polymorphonuclear neutrophils (PMNs) function as "Trojan horse" vehicles for bacterial dispersal and as modulators of the Th1 adaptive immunity in infection.
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7
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Maciejewska A, Bednarczyk B, Lugowski C, Lukasiewicz J. Structural Studies of the Lipopolysaccharide Isolated from Plesiomonas shigelloides O22:H3 (CNCTC 90/89). Int J Mol Sci 2020; 21:ijms21186788. [PMID: 32947917 PMCID: PMC7555982 DOI: 10.3390/ijms21186788] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/04/2020] [Accepted: 09/14/2020] [Indexed: 02/02/2023] Open
Abstract
Plesiomonas shigelloides is a Gram-negative, rod-shaped bacterium which causes foodborne intestinal infections, including gastroenteritis. It is one of the most frequent causes of travellers’ diarrhoea. Lipopolysaccharide (LPS, endotoxin), an important virulence factor of the species, is in most cases characterised by a smooth character, demonstrated by the presence of all regions, such as lipid A, core oligosaccharide, and O-specific polysaccharide, where the latter part determines O-serotype. P. shigelloides LPS is still a poorly characterised virulence factor considering a “translation” of the particular O-serotype into chemical structure. To date, LPS structure has only been elucidated for 15 strains out of 102 O-serotypes. Structures of the new O-specific polysaccharide and core oligosaccharide of P. shigelloides from the Czechoslovak National Collection of Type Cultures CNCTC 90/89 LPS (O22), investigated by chemical analysis, mass spectrometry, and 1H,13C nuclear magnetic resonance (NMR) spectroscopy, have now been reported. The pentasaccharide repeating unit of the O-specific polysaccharide is built of one d-QuipNAc and is rich in four d-GalpNAcAN residues. Moreover, the new core oligosaccharide shares common features of other P. shigelloides endotoxins, i.e., the lack of phosphate groups and the presence of uronic acids.
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Lanne ABM, Goode A, Prattley C, Kumari D, Drasbek MR, Williams P, Conde-Álvarez R, Moriyón I, Bonev BB. Molecular recognition of lipopolysaccharide by the lantibiotic nisin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:83-92. [PMID: 30296414 DOI: 10.1016/j.bbamem.2018.10.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 10/02/2018] [Accepted: 10/03/2018] [Indexed: 01/01/2023]
Abstract
Nisin is a lanthionine antimicrobial effective against diverse Gram-positive bacteria and is used as a food preservative worldwide. Its action is mediated by pyrophosphate recognition of the bacterial cell wall receptors lipid II and undecaprenyl pyrophosphate. Nisin/receptor complexes disrupt cytoplasmic membranes, inhibit cell wall synthesis and dysregulate bacterial cell division. Gram-negative bacteria are much more tolerant to antimicrobials including nisin. In contrast to Gram-positives, Gram-negative bacteria possess an outer membrane, the major constituent of which is lipopolysaccharide (LPS). This contains surface exposed phosphate and pyrophosphate groups and hence can be targeted by nisin. Here we describe the impact of LPS on membrane stability in response to nisin and the molecular interactions occurring between nisin and membrane-embedded LPS from different Gram-negative bacteria. Dye release from liposomes shows enhanced susceptibility to nisin in the presence of LPS, particularly rough LPS chemotypes that lack an O-antigen whereas LPS from microorganisms sharing similar ecological niches with antimicrobial producers provides only modest enhancement. Increased susceptibility was observed with LPS from pathogenic Klebsiella pneumoniae compared to LPS from enteropathogenic Salmonella enterica and gut commensal Escherichia coli. LPS from Brucella melitensis, an intra-cellular pathogen which is adapted to invade professional and non-professional phagocytes, appears to be refractory to nisin. Molecular complex formation between nisin and LPS was studied by solid state MAS NMR and revealed complex formation between nisin and LPS from most organisms investigated except B. melitensis. LPS/nisin complex formation was confirmed in outer membrane extracts from E. coli.
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Affiliation(s)
- Alice B M Lanne
- School of Life Sciences, QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - Alice Goode
- School of Life Sciences, QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - Charlotte Prattley
- School of Life Sciences, QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - Divya Kumari
- School of Life Sciences, QMC, University of Nottingham, Nottingham NG7 2UH, UK
| | - Mette Ryun Drasbek
- DuPont Nutrition Biosciences ApS, Edwin Rahrs Vej 38, DK-8220 Brabrand, Denmark
| | - Paul Williams
- School of Life Sciences, CBS, University of Nottingham, Nottingham NG7 2RD, UK
| | - Raquel Conde-Álvarez
- Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, and Departamento de Microbiología y Parasitología, Universidad de Navarra, c/Irunlarrea 1, 31008 Pamplona, Spain
| | - Ignacio Moriyón
- Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, and Departamento de Microbiología y Parasitología, Universidad de Navarra, c/Irunlarrea 1, 31008 Pamplona, Spain
| | - Boyan B Bonev
- School of Life Sciences, QMC, University of Nottingham, Nottingham NG7 2UH, UK.
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Salvador-Bescós M, Gil-Ramírez Y, Zúñiga-Ripa A, Martínez-Gómez E, de Miguel MJ, Muñoz PM, Cloeckaert A, Zygmunt MS, Moriyón I, Iriarte M, Conde-Álvarez R. WadD, a New Brucella Lipopolysaccharide Core Glycosyltransferase Identified by Genomic Search and Phenotypic Characterization. Front Microbiol 2018; 9:2293. [PMID: 30319590 PMCID: PMC6171495 DOI: 10.3389/fmicb.2018.02293] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 09/07/2018] [Indexed: 01/20/2023] Open
Abstract
Brucellosis, an infectious disease caused by Brucella, is one of the most extended bacterial zoonosis in the world and an important cause of economic losses and human suffering. The lipopolysaccharide (LPS) of Brucella plays a major role in virulence as it impairs normal recognition by the innate immune system and delays the immune response. The LPS core is a branched structure involved in resistance to complement and polycationic peptides, and mutants in glycosyltransferases required for the synthesis of the lateral branch not linked to the O-polysaccharide (O-PS) are attenuated and have been proposed as vaccine candidates. For this reason, the complete understanding of the genes involved in the synthesis of this LPS section is of particular interest. The chemical structure of the Brucella LPS core suggests that, in addition to the already identified WadB and WadC glycosyltransferases, others could be implicated in the synthesis of this lateral branch. To clarify this point, we identified and constructed mutants in 11 ORFs encoding putative glycosyltransferases in B. abortus. Four of these ORFs, regulated by the virulence regulator MucR (involved in LPS synthesis) or the BvrR/BvrS system (implicated in the synthesis of surface components), were not required for the synthesis of a complete LPS neither for virulence or interaction with polycationic peptides and/or complement. Among the other seven ORFs, six seemed not to be required for the synthesis of the core LPS since the corresponding mutants kept the O-PS and reacted as the wild type with polyclonal sera. Interestingly, mutant in ORF BAB1_0953 (renamed wadD) lost reactivity against antibodies that recognize the core section while kept the O-PS. This suggests that WadD is a new glycosyltransferase adding one or more sugars to the core lateral branch. WadD mutants were more sensitive than the parental strain to components of the innate immune system and played a role in chronic stages of infection. These results corroborate and extend previous work indicating that the Brucella LPS core is a branched structure that constitutes a steric impairment preventing the elements of the innate immune system to fight against Brucella.
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Affiliation(s)
- Miriam Salvador-Bescós
- Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, and Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Yolanda Gil-Ramírez
- Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, and Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Amaia Zúñiga-Ripa
- Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, and Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Estrella Martínez-Gómez
- Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, and Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - María J de Miguel
- Unidad de Tecnología en Producción y Sanidad Animal, Centro de Investigación y Tecnología Agroalimentaria, Instituto Agroalimentario de Aragón - IA2 (CITA - Universidad de Zaragoza), Zaragoza, Spain
| | - Pilar M Muñoz
- Unidad de Tecnología en Producción y Sanidad Animal, Centro de Investigación y Tecnología Agroalimentaria, Instituto Agroalimentario de Aragón - IA2 (CITA - Universidad de Zaragoza), Zaragoza, Spain
| | - Axel Cloeckaert
- Institut National de la Recherche Agronomique, Université François Rabelais de Tours, UMR 1282, Nouzilly, France
| | - Michel S Zygmunt
- Institut National de la Recherche Agronomique, Université François Rabelais de Tours, UMR 1282, Nouzilly, France
| | - Ignacio Moriyón
- Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, and Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Maite Iriarte
- Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, and Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Raquel Conde-Álvarez
- Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, and Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
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10
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Martínez-Gómez E, Ståhle J, Gil-Ramírez Y, Zúñiga-Ripa A, Zaccheus M, Moriyón I, Iriarte M, Widmalm G, Conde-Álvarez R. Genomic Insertion of a Heterologous Acetyltransferase Generates a New Lipopolysaccharide Antigenic Structure in Brucella abortus and Brucella melitensis. Front Microbiol 2018; 9:1092. [PMID: 29887851 PMCID: PMC5981137 DOI: 10.3389/fmicb.2018.01092] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 05/07/2018] [Indexed: 12/31/2022] Open
Abstract
Brucellosis is a bacterial zoonosis of worldwide distribution caused by bacteria of the genus Brucella. In Brucella abortus and Brucella melitensis, the major species infecting domestic ruminants, the smooth lipopolysaccharide (S-LPS) is a virulence factor. This S-LPS carries a N-formyl-perosamine homopolymer O-polysaccharide that is the major antigen in serodiagnostic tests and is required for virulence. We report that the Brucella O-PS can be structurally and antigenically modified using wbdR, the acetyl-transferase gene involved in N-acetyl-perosamine synthesis in Escherichia coli O157:H7. Brucella constructs carrying plasmidic wbdR expressed a modified O-polysaccharide but were unstable, a problem circumvented by inserting wbdR into a neutral site of chromosome II. As compared to wild-type bacteria, both kinds of wbdR constructs expressed shorter O-polysaccharides and NMR analyses showed that they contained both N-formyl and N-acetyl-perosamine. Moreover, deletion of the Brucella formyltransferase gene wbkC in wbdR constructs generated bacteria producing only N-acetyl-perosamine homopolymers, proving that wbdR can replace for wbkC. Absorption experiments with immune sera revealed that the wbdR constructs triggered antibodies to new immunogenic epitope(s) and the use of monoclonal antibodies proved that B. abortus and B. melitensis wbdR constructs respectively lacked the A or M epitopes, and the absence of the C epitope in both backgrounds. The wbdR constructs showed resistance to polycations similar to that of the wild-type strains but displayed increased sensitivity to normal serum similar to that of a per R mutant. In mice, the wbdR constructs produced chronic infections and triggered antibody responses that can be differentiated from those evoked by the wild-type strain in S-LPS ELISAs. These results open the possibilities of developing brucellosis vaccines that are both antigenically tagged and lack the diagnostic epitopes of virulent field strains, thereby solving the diagnostic interference created by current vaccines against Brucella.
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Affiliation(s)
- Estrella Martínez-Gómez
- Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Jonas Ståhle
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden
| | - Yolanda Gil-Ramírez
- Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Amaia Zúñiga-Ripa
- Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Mona Zaccheus
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden
| | - Ignacio Moriyón
- Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Maite Iriarte
- Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
| | - Göran Widmalm
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden
| | - Raquel Conde-Álvarez
- Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, Departamento de Microbiología y Parasitología, Universidad de Navarra, Pamplona, Spain
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11
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Conde-Álvarez R, Palacios-Chaves L, Gil-Ramírez Y, Salvador-Bescós M, Bárcena-Varela M, Aragón-Aranda B, Martínez-Gómez E, Zúñiga-Ripa A, de Miguel MJ, Bartholomew TL, Hanniffy S, Grilló MJ, Vences-Guzmán MÁ, Bengoechea JA, Arce-Gorvel V, Gorvel JP, Moriyón I, Iriarte M. Identification of lptA, lpxE, and lpxO, Three Genes Involved in the Remodeling of Brucella Cell Envelope. Front Microbiol 2018; 8:2657. [PMID: 29375522 PMCID: PMC5767591 DOI: 10.3389/fmicb.2017.02657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 12/20/2017] [Indexed: 12/19/2022] Open
Abstract
The brucellae are facultative intracellular bacteria that cause a worldwide extended zoonosis. One of the pathogenicity mechanisms of these bacteria is their ability to avoid rapid recognition by innate immunity because of a reduction of the pathogen-associated molecular pattern (PAMP) of the lipopolysaccharide (LPS), free-lipids, and other envelope molecules. We investigated the Brucella homologs of lptA, lpxE, and lpxO, three genes that in some pathogens encode enzymes that mask the LPS PAMP by upsetting the core-lipid A charge/hydrophobic balance. Brucella lptA, which encodes a putative ethanolamine transferase, carries a frame-shift in B. abortus but not in other Brucella spp. and phylogenetic neighbors like the opportunistic pathogen Ochrobactrum anthropi. Consistent with the genomic evidence, a B. melitensis lptA mutant lacked lipid A-linked ethanolamine and displayed increased sensitivity to polymyxin B (a surrogate of innate immunity bactericidal peptides), while B. abortus carrying B. melitensis lptA displayed increased resistance. Brucella lpxE encodes a putative phosphatase acting on lipid A or on a free-lipid that is highly conserved in all brucellae and O. anthropi. Although we found no evidence of lipid A dephosphorylation, a B. abortus lpxE mutant showed increased polymyxin B sensitivity, suggesting the existence of a hitherto unidentified free-lipid involved in bactericidal peptide resistance. Gene lpxO putatively encoding an acyl hydroxylase carries a frame-shift in all brucellae except B. microti and is intact in O. anthropi. Free-lipid analysis revealed that lpxO corresponded to olsC, the gene coding for the ornithine lipid (OL) acyl hydroxylase active in O. anthropi and B. microti, while B. abortus carrying the olsC of O. anthropi and B. microti synthesized hydroxylated OLs. Interestingly, mutants in lptA, lpxE, or olsC were not attenuated in dendritic cells or mice. This lack of an obvious effect on virulence together with the presence of the intact homolog genes in O. anthropi and B. microti but not in other brucellae suggests that LptA, LpxE, or OL β-hydroxylase do not significantly alter the PAMP properties of Brucella LPS and free-lipids and are therefore not positively selected during the adaptation to intracellular life.
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Affiliation(s)
- Raquel Conde-Álvarez
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
| | - Leyre Palacios-Chaves
- Instituto de Agrobiotecnología, Consejo Superior de Investigaciones Científicas - Universidad Pública de Navarra - Gobierno de Navarra, Pamplona, Spain
| | - Yolanda Gil-Ramírez
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
| | - Miriam Salvador-Bescós
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
| | - Marina Bárcena-Varela
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
| | - Beatriz Aragón-Aranda
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
| | - Estrella Martínez-Gómez
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
| | - Amaia Zúñiga-Ripa
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
| | - María J de Miguel
- Unidad de Producción y Sanidad Animal, Instituto Agroalimentario de Aragón, Centro de Investigación y Tecnología Agroalimentaria de Aragón - Universidad de Zaragoza, Zaragoza, Spain
| | - Toby Leigh Bartholomew
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - Sean Hanniffy
- Institut National de la Santé et de la Recherche Médicale, U1104, Centre National de la Recherche Scientifique UMR7280, Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University UM2, Marseille, France
| | - María-Jesús Grilló
- Instituto de Agrobiotecnología, Consejo Superior de Investigaciones Científicas - Universidad Pública de Navarra - Gobierno de Navarra, Pamplona, Spain
| | | | - José A Bengoechea
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - Vilma Arce-Gorvel
- Institut National de la Santé et de la Recherche Médicale, U1104, Centre National de la Recherche Scientifique UMR7280, Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University UM2, Marseille, France
| | - Jean-Pierre Gorvel
- Institut National de la Santé et de la Recherche Médicale, U1104, Centre National de la Recherche Scientifique UMR7280, Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University UM2, Marseille, France
| | - Ignacio Moriyón
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
| | - Maite Iriarte
- Universidad de Navarra, Facultad de Medicina, Departamento de Microbiología y Parasitología, Instituto de Salud Tropical (ISTUN) e Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain
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12
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Vaccine development targeting lipopolysaccharide structure modification. Microbes Infect 2017; 20:455-460. [PMID: 29233768 DOI: 10.1016/j.micinf.2017.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 11/23/2017] [Accepted: 11/27/2017] [Indexed: 01/01/2023]
Abstract
Vaccines are one of the most important methods for preventing infectious disease. Structural modification of lipopolysaccharide (LPS) provides a strategy for the development of live attenuated vaccines, either by altering the immunogenicity or by attenuating virulence of the bacteria. This review summarizes various approaches that utilize LPS mutants as whole-cell vaccines.
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13
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Casabuono AC, Czibener C, Del Giudice MG, Valguarnera E, Ugalde JE, Couto AS. New Features in the Lipid A Structure of Brucella suis and Brucella abortus Lipopolysaccharide. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:2716-2723. [PMID: 28924631 DOI: 10.1007/s13361-017-1805-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/18/2017] [Accepted: 08/26/2017] [Indexed: 06/07/2023]
Abstract
Brucellaceae are Gram-negative bacteria that cause brucellosis, one of the most distributed worldwide zoonosis, transmitted to humans by contact with either infected animals or their products. The lipopolysaccharide exposed on the cell surface has been intensively studied and is considered a major virulence factor of Brucella. In the last years, structural studies allowed the determination of new structures in the core oligosaccharide and the O-antigen of this lipopolysaccharide. In this work, we have reinvestigated the lipid A structure isolated from B. suis and B. abortus lipopolysaccharides. A detailed study by MALDI-TOF mass spectrometry in the positive and negative ion modes of the lipid A moieties purified from both species was performed. Interestingly, a new feature was detected: the presence of a pyrophosphorylethanolamine residue substituting the backbone. LID-MS/MS analysis of some of the detected ions allowed assurance that the Lipid A structure composed by the diGlcN3N disaccharide, mainly hexa-acylated and penta-acylated, bearing one phosphate and one pyrophosphorylethanolamine residue. Graphical abstract ᅟ.
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Affiliation(s)
- Adriana C Casabuono
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Orgánica - Consejo Nacional de Investigaciones Científicas y Técnicas, Centro de Investigación en Hidratos de Carbono (CIHIDECAR), Ciudad Universitaria, Intendente Güiraldes 2160, C1428GA, Buenos Aires, Argentina
| | - Cecilia Czibener
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde", IIB-INTECH, CONICET, Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Mariela G Del Giudice
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde", IIB-INTECH, CONICET, Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Ezequiel Valguarnera
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde", IIB-INTECH, CONICET, Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Juan E Ugalde
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde", IIB-INTECH, CONICET, Universidad Nacional de San Martín, San Martín, Buenos Aires, Argentina
| | - Alicia S Couto
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Orgánica - Consejo Nacional de Investigaciones Científicas y Técnicas, Centro de Investigación en Hidratos de Carbono (CIHIDECAR), Ciudad Universitaria, Intendente Güiraldes 2160, C1428GA, Buenos Aires, Argentina.
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14
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Mandal S, Duncombe L, Ganesh NV, Sarkar S, Howells L, Hogarth PJ, Bundle DR, McGiven J. Novel Solutions for Vaccines and Diagnostics To Combat Brucellosis. ACS CENTRAL SCIENCE 2017; 3:224-231. [PMID: 28386600 PMCID: PMC5364457 DOI: 10.1021/acscentsci.7b00019] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Indexed: 05/02/2023]
Abstract
Brucellosis is diagnosed by detection of antibodies in the blood of animals and humans that are specific for two carbohydrate antigens, termed A and M, which are present concurrently in a single cell wall O-polysaccharide. Animal brucellosis vaccines contain these antigenic determinants, and consequently infected and vaccinated animals cannot be differentiated as both groups produce A and M specific antibodies. We hypothesized that chemical synthesis of a pure A vaccine would offer unique identification of infected animals by a synthetic M diagnostic antigen that would not react with antibodies generated by this vaccine. Two forms of the A antigen, a hexasaccharide and a heptasaccharide conjugated to tetanus toxoid via reducing and nonreducing terminal sugars, were synthesized and used as lead vaccine candidates. Mouse antibody profiles to these immunogens showed that to avoid reaction with diagnostic M antigen it was essential to maximize the induction of anti-A antibodies that bind internal oligosaccharide sequences and minimize production of antibodies directed toward the terminal nonreducing monosaccharide. This objective was achieved by conjugation of Brucella O-polysaccharide to tetanus toxoid via its periodate oxidized terminal nonreducing monosaccharide, thereby destroying terminal epitopes and focusing the antibody response on internal A epitopes. This establishes the method to resolve the decades-long challenge of how to create effective brucellosis vaccines without compromising diagnosis of infected animals.
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Affiliation(s)
| | - Lucy Duncombe
- Department
of Bacteriology, Animal & Plant Health Agency, OIE Brucellosis
Reference Laboratory, FAO/WHO Collaborating
Centre for Brucellosis, Woodham Lane, Addlestone, Surrey, United Kingdom, KT15 3NB
| | - N. Vijaya Ganesh
- Department
of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Susmita Sarkar
- Department
of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Laurence Howells
- Department
of Bacteriology, Animal & Plant Health Agency, OIE Brucellosis
Reference Laboratory, FAO/WHO Collaborating
Centre for Brucellosis, Woodham Lane, Addlestone, Surrey, United Kingdom, KT15 3NB
| | - Philip J. Hogarth
- Vaccine
Immunology Team, Department of Bacteriology, Animal & Plant Health Agency, Woodham Lane, Addlestone, Surrey, United Kingdom, KT15 3NB
| | - David R. Bundle
- Department
of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
- Department of Chemistry,
University
of Alberta, Edmonton, Alberta T6G 2G2, Canada. E-mail:
| | - John McGiven
- Department
of Bacteriology, Animal & Plant Health Agency, OIE Brucellosis
Reference Laboratory, FAO/WHO Collaborating
Centre for Brucellosis, Woodham Lane, Addlestone, Surrey, United Kingdom, KT15 3NB
- FAO/WHO Collaborating Centre for
Brucellosis, OIE Brucellosis Reference Laboratory, Department of Bacteriology,
Animal & Plant Health Agency, Woodham Lane, Addlestone, Surrey,
United Kingdom, KT15 3NB. E-mail:
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15
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N-Formyl-Perosamine Surface Homopolysaccharides Hinder the Recognition of Brucella abortus by Mouse Neutrophils. Infect Immun 2016; 84:1712-21. [PMID: 27001541 DOI: 10.1128/iai.00137-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 03/15/2016] [Indexed: 12/30/2022] Open
Abstract
Brucella abortus is an intracellular pathogen of monocytes, macrophages, dendritic cells, and placental trophoblasts. This bacterium causes a chronic disease in bovines and in humans. In these hosts, the bacterium also invades neutrophils; however, it fails to replicate and just resists the killing action of these leukocytes without inducing significant activation or neutrophilia. Moreover, B. abortus causes the premature cell death of human neutrophils. In the murine model, the bacterium is found within macrophages and dendritic cells at early times of infection but seldom in neutrophils. Based on this observation, we explored the interaction of mouse neutrophils with B. abortus In contrast to human, dog, and bovine neutrophils, naive mouse neutrophils fail to recognize smooth B. abortus bacteria at early stages of infection. Murine normal serum components do not opsonize smooth Brucella strains, and neutrophil phagocytosis is achieved only after the appearance of antibodies. Alternatively, mouse normal serum is capable of opsonizing rough Brucella mutants. Despite this, neutrophils still fail to kill Brucella, and the bacterium induces cell death of murine leukocytes. In addition, mouse serum does not opsonize Yersinia enterocolitica O:9, a bacterium displaying the same surface polysaccharide antigen as smooth B. abortus Therefore, the lack of murine serum opsonization and absence of murine neutrophil recognition are specific, and the molecules responsible for the Brucella camouflage are N-formyl-perosamine surface homopolysaccharides. Although the mouse is a valuable model for understanding the immunobiology of brucellosis, direct extrapolation from one animal system to another has to be undertaken with caution.
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16
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Ducrotoy MJ, Conde-Álvarez R, Blasco JM, Moriyón I. A review of the basis of the immunological diagnosis of ruminant brucellosis. Vet Immunol Immunopathol 2016; 171:81-102. [DOI: 10.1016/j.vetimm.2016.02.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 01/07/2016] [Accepted: 02/02/2016] [Indexed: 01/18/2023]
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17
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Fontana C, Conde-Álvarez R, Ståhle J, Holst O, Iriarte M, Zhao Y, Arce-Gorvel V, Hanniffy S, Gorvel JP, Moriyón I, Widmalm G. Structural Studies of Lipopolysaccharide-defective Mutants from Brucella melitensis Identify a Core Oligosaccharide Critical in Virulence. J Biol Chem 2016; 291:7727-41. [PMID: 26867577 PMCID: PMC4817197 DOI: 10.1074/jbc.m115.701540] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Indexed: 11/07/2022] Open
Abstract
The structures of the lipooligosaccharides from Brucella melitensis mutants affected in the WbkD and ManBcore proteins have been fully characterized using NMR spectroscopy. The results revealed that disruption of wbkD gives rise to a rough lipopolysaccharide (R-LPS) with a complete core structure (β-d-Glcp-(1→4)-α-Kdop-(2→4)[β-d-GlcpN-(1→6)-β-d-GlcpN-(1→4)[β-d-GlcpN-(1→6)]-β-d-GlcpN-(1→3)-α-d-Manp-(1→5)]-α-Kdop-(2→6)-β-d-GlcpN3N4P-(1→6)-α-d-GlcpN3N1P), in addition to components lacking one of the terminal β-d-GlcpN and/or the β-d-Glcp residues (48 and 17%, respectively). These structures were identical to those of the R-LPS from B. melitensis EP, a strain simultaneously expressing both smooth and R-LPS, also studied herein. In contrast, disruption of manBcore gives rise to a deep-rough pentasaccharide core (β-d-Glcp-(1→4)-α-Kdop-(2→4)-α-Kdop-(2→6)-β-d-GlcpN3N4P-(1→6)-α-d-GlcpN3N1P) as the major component (63%), as well as a minor tetrasaccharide component lacking the terminal β-d-Glcp residue (37%). These results are in agreement with the predicted functions of the WbkD (glycosyltransferase involved in the biosynthesis of the O-antigen) and ManBcore proteins (phosphomannomutase involved in the biosynthesis of a mannosyl precursor needed for the biosynthesis of the core and O-antigen). We also report that deletion of B. melitensis wadC removes the core oligosaccharide branch not linked to the O-antigen causing an increase in overall negative charge of the remaining LPS inner section. This is in agreement with the mannosyltransferase role predicted for WadC and the lack of GlcpN residues in the defective core oligosaccharide. Despite carrying the O-antigen essential in B. melitensis virulence, the core deficiency in the wadC mutant structure resulted in a more efficient detection by innate immunity and attenuation, proving the role of the β-d-GlcpN-(1→6)-β-d-GlcpN-(1→4)[β-d-GlcpN-(1→6)]-β-d-GlcpN-(1→3)-α-d-Manp-(1→5) structure in virulence.
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Affiliation(s)
- Carolina Fontana
- From the Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden
| | - Raquel Conde-Álvarez
- the Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, and Departamento de Microbiología y Parasitología, Universidad de Navarra, c/Irunlarrea 1, 31008 Pamplona, Spain
| | - Jonas Ståhle
- From the Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden
| | - Otto Holst
- the Division of Structural Biochemistry, Leibniz-Center for Medicine and Biosciences, Priority Area Asthma and Allergy, Research Center Borstel, Airway Research Center North, Member of the German Center for Lung Research, D-23845 Borstel, Germany
| | - Maite Iriarte
- the Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, and Departamento de Microbiología y Parasitología, Universidad de Navarra, c/Irunlarrea 1, 31008 Pamplona, Spain
| | - Yun Zhao
- the Centre d'Immunologie de Marseille-Luminy Aix-Marseille University, UM2 Marseille, France
| | - Vilma Arce-Gorvel
- the Centre d'Immunologie de Marseille-Luminy Aix-Marseille University, UM2 Marseille, France, INSERM, U1104 Marseille, France, and CNRS, UMR7280 Marseille, France
| | - Seán Hanniffy
- the Centre d'Immunologie de Marseille-Luminy Aix-Marseille University, UM2 Marseille, France, INSERM, U1104 Marseille, France, and CNRS, UMR7280 Marseille, France
| | - Jean-Pierre Gorvel
- the Centre d'Immunologie de Marseille-Luminy Aix-Marseille University, UM2 Marseille, France, INSERM, U1104 Marseille, France, and CNRS, UMR7280 Marseille, France
| | - Ignacio Moriyón
- the Instituto de Salud Tropical, Instituto de Investigación Sanitaria de Navarra, and Departamento de Microbiología y Parasitología, Universidad de Navarra, c/Irunlarrea 1, 31008 Pamplona, Spain
| | - Göran Widmalm
- From the Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden,
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18
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Mancilla M. Smooth to Rough Dissociation in Brucella: The Missing Link to Virulence. Front Cell Infect Microbiol 2016; 5:98. [PMID: 26779449 PMCID: PMC4700419 DOI: 10.3389/fcimb.2015.00098] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 12/10/2015] [Indexed: 11/24/2022] Open
Abstract
Dissociation encompasses changes in a series of phenotypes: colony and cell morphology, inmunological and biochemical reactions and virulence. The concept is generally associated to the in vitro transition between smooth (S) and rough (R) colonies, a phenotypic observation in Gram-negative bacteria commonly made since the beginning of microbiology as a science. It is also well known that the loss of the O-polysaccharide, the most external lipopolysaccharide (LPS) moiety, triggers the change in the colony phenotype. Although dissociation is related to one of the most basic features used to distinguish between species, i.e., colony morphology, and, in the case of pathogens, predict their virulence behavior, it has been considered a laboratory artifact and thus did not gain further attention. However, recent insights into genetics and pathogenesis of members of Brucella, causative agents of brucellosis, have brought a new outlook on this experimental fact, suggesting that it plays a role beyond the laboratory observations. In this perspective article, the current knowledge on Brucella LPS genetics and its connection with dissociation in the frame of evolution is discussed. Latest reports support the notion that, by means of a better understanding of genetic pathways linked to R phenotype and the biological impact of this intriguing "old" phenomenon, unexpected applications can be achieved.
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Affiliation(s)
- Marcos Mancilla
- Research and Development Department, ADL Diagnostic Chile Ltd.Puerto Montt, Chile
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Barquero-Calvo E, Mora-Cartín R, Arce-Gorvel V, de Diego JL, Chacón-Díaz C, Chaves-Olarte E, Guzmán-Verri C, Buret AG, Gorvel JP, Moreno E. Brucella abortus Induces the Premature Death of Human Neutrophils through the Action of Its Lipopolysaccharide. PLoS Pathog 2015; 11:e1004853. [PMID: 25946018 PMCID: PMC4422582 DOI: 10.1371/journal.ppat.1004853] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 04/03/2015] [Indexed: 01/18/2023] Open
Abstract
Most bacterial infections induce the activation of polymorphonuclear neutrophils (PMNs), enhance their microbicidal function, and promote the survival of these leukocytes for protracted periods of time. Brucella abortus is a stealthy pathogen that evades innate immunity, barely activates PMNs, and resists the killing mechanisms of these phagocytes. Intriguing clinical signs observed during brucellosis are the low numbers of Brucella infected PMNs in the target organs and neutropenia in a proportion of the patients; features that deserve further attention. Here we demonstrate that B. abortus prematurely kills human PMNs in a dose-dependent and cell-specific manner. Death of PMNs is concomitant with the intracellular Brucella lipopolysaccharide (Br-LPS) release within vacuoles. This molecule and its lipid A reproduce the premature cell death of PMNs, a phenomenon associated to the low production of proinflammatory cytokines. Blocking of CD14 but not TLR4 prevents the Br-LPS-induced cell death. The PMNs cell death departs from necrosis, NETosis and classical apoptosis. The mechanism of PMN cell death is linked to the activation of NADPH-oxidase and a modest but steadily increase of ROS mediators. These effectors generate DNA damage, recruitments of check point kinase 1, caspases 5 and to minor extent of caspase 4, RIP1 and Ca++ release. The production of IL-1β by PMNs was barely stimulated by B. abortus infection or Br-LPS treatment. Likewise, inhibition of caspase 1 did not hamper the Br-LPS induced PMN cell death, suggesting that the inflammasome pathway was not involved. Although activation of caspases 8 and 9 was observed, they did not seem to participate in the initial triggering mechanisms, since inhibition of these caspases scarcely blocked PMN cell death. These findings suggest a mechanism for neutropenia in chronic brucellosis and reveal a novel Brucella-host cross-talk through which B. abortus is able to hinder the innate function of PMN. The absence of obvious clinical symptoms during the early stages of brucellosis is linked to the Brucella stealthy strategy and its non-canonical PAMPs, which are low PRRs agonists. Still, there are clinical profiles that require explanation. For instance ‒despite the fact that neutrophils readily ingest Brucella during the onset of infection, brucellosis courses without neutrophilia, and just a low number of infected neutrophils are present in target organs. In the chronic phases, a significant proportion of the patients display absolute neutropenia and bone marrow pancytopenia linked to the myeloid cell linage. Examination of the Brucella infected bone marrow reveals granulomas and phagocytosis of myeloid cells. Based on these observations we explored the fate of native neutrophils during their interaction with Brucella. We found that the bacterium induces the premature cell death of neutrophils without inducing proinflammatory phenotypic changes. This event was reproduced by the lipid A of the Brucella LPS and depends on NADPH-oxidase activation and low ROS formation. We believe that this phenomenon explains ‒at least in part‒ the hematological and histological profiles observed during brucellosis. In addition, it may be that dying Brucella-infected neutrophils serve as “Trojan horse” vehicles for infecting phagocytic cells without promoting activation.
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Affiliation(s)
- Elías Barquero-Calvo
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
- Centro de Investigación en Enfermedades Tropicales, Universidad de Costa Rica, San José, Costa Rica
| | - Ricardo Mora-Cartín
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Vilma Arce-Gorvel
- Centre d'Immunologie de Marseille-Luminy (CIML), Aix-Marseille University, UM2, Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1104, Marseille, France
- Centre National de la Recherche Scientifique (CNRS), UMR7280, Marseille, France
| | - Juana L. de Diego
- Department of Cell Microbiology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Carlos Chacón-Díaz
- Centro de Investigación en Enfermedades Tropicales, Universidad de Costa Rica, San José, Costa Rica
| | - Esteban Chaves-Olarte
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
- Centro de Investigación en Enfermedades Tropicales, Universidad de Costa Rica, San José, Costa Rica
| | - Caterina Guzmán-Verri
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
- Centro de Investigación en Enfermedades Tropicales, Universidad de Costa Rica, San José, Costa Rica
| | - Andre G. Buret
- Biological Sciences, Inflammation Research Network, University of Calgary, Calgary, Alberta, Canada
| | - Jean-Pierre Gorvel
- Centre d'Immunologie de Marseille-Luminy (CIML), Aix-Marseille University, UM2, Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1104, Marseille, France
- Centre National de la Recherche Scientifique (CNRS), UMR7280, Marseille, France
- * E-mail: (JPG); (EM)
| | - Edgardo Moreno
- Programa de Investigación en Enfermedades Tropicales, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
- * E-mail: (JPG); (EM)
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Diagnostic performance of serological tests for swine brucellosis in the presence of false positive serological reactions. J Microbiol Methods 2015; 111:57-63. [DOI: 10.1016/j.mimet.2015.02.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 01/27/2015] [Accepted: 02/02/2015] [Indexed: 11/19/2022]
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Improved serodiagnosis of bovine brucellosis by novel synthetic oligosaccharide antigens representing the capping m epitope elements of Brucella O-polysaccharide. J Clin Microbiol 2015; 53:1204-10. [PMID: 25653412 DOI: 10.1128/jcm.03185-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Members of the genus Brucella have cell wall characteristics of Gram-negative bacteria, which in the most significant species includes O-polysaccharide (OPS). Serology is the most cost-effective means of detecting brucellosis, as infection with smooth strains of Brucella leads to the induction of high antibody titers against the OPS, an unbranched homopolymer of 4,6-dideoxy-4-formamido-D-mannopyranosyl residues (D-Rha4NFo) that are variably α(1→2)- and α(1→3)-linked. Six d-Rha4NFo homo-oligosaccharides were synthesized, each containing a single α(1→3) link but with a varied number of α(1→2) links. After conjugation to bovine serum albumin (BSA), glycoconjugates 1 to 6 were used to develop individual indirect enzyme-linked immunosorbent assays (iELISAs). The diagnostic capabilities of these antigens were applied to panels of cattle serum samples, including those falsely positive in conventional assays, and the results were compared with those of the complement fixation test (CFT), serum agglutination test (SAT), fluorescent polarization assay (FPA), smooth lipopolysaccharide (sLPS) iELISA, and competitive enzyme-linked immunosorbent assay (cELISA) methods. Results from field serum samples demonstrated that all of the synthetic antigens had excellent diagnostic capabilities. Assays developed with the α(1→3)-linked disaccharide conjugate 1 were the best at resolving false-positive serological results. This was supported by the results from serum samples derived from experimentally infected cattle. Data from synthetic trisaccharide antigens 2 and 3 and tetrasaccharide antigen 4 identified an OPS epitope equally common to all Brucella abortus and Brucella melitensis strains but unique to Brucella. Synthetic oligosaccharide conjugates function as effective surrogates for naturally derived antigens. The creation of discrete OPS epitope antigens reveals not only the previously untapped diagnostic potential within this key diagnostic structure but also holds significance for the design of brucellosis vaccines and diagnostics that enable the differentiation of infected from vaccinated animals.
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22
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Ronneau S, Moussa S, Barbier T, Conde-Álvarez R, Zuniga-Ripa A, Moriyon I, Letesson JJ. Brucella, nitrogen and virulence. Crit Rev Microbiol 2014; 42:507-25. [PMID: 25471320 DOI: 10.3109/1040841x.2014.962480] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The brucellae are α-Proteobacteria causing brucellosis, an important zoonosis. Although multiplying in endoplasmic reticulum-derived vacuoles, they cause no cell death, suggesting subtle but efficient use of host resources. Brucellae are amino-acid prototrophs able to grow with ammonium or use glutamate as the sole carbon-nitrogen source in vitro. They contain more than twice amino acid/peptide/polyamine uptake genes than the amino-acid auxotroph Legionella pneumophila, which multiplies in a similar vacuole, suggesting a different nutritional strategy. During these two last decades, many mutants of key actors in nitrogen metabolism (transporters, enzymes, regulators, etc.) have been described to be essential for full virulence of brucellae. Here, we review the genomic and experimental data on Brucella nitrogen metabolism and its connection with virulence. An analysis of various aspects of this metabolism (transport, assimilation, biosynthesis, catabolism, respiration and regulation) has highlighted differences and similarities in nitrogen metabolism with other α-Proteobacteria. Together, these data suggest that, during their intracellular life cycle, the brucellae use various nitrogen sources for biosynthesis, catabolism and respiration following a strategy that requires prototrophy and a tight regulation of nitrogen use.
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Affiliation(s)
| | - Simon Moussa
- a UNamur, URBM 61 rue de Bruxelles , Namur , Belgium and
| | | | - Raquel Conde-Álvarez
- b Departamento de Microbiología , Edificio de Investigación, Universidad de Navarra , Pamplona , Spain
| | - Amaia Zuniga-Ripa
- b Departamento de Microbiología , Edificio de Investigación, Universidad de Navarra , Pamplona , Spain
| | - Ignacio Moriyon
- b Departamento de Microbiología , Edificio de Investigación, Universidad de Navarra , Pamplona , Spain
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23
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Soler-Lloréns P, Gil-Ramírez Y, Zabalza-Baranguá A, Iriarte M, Conde-Álvarez R, Zúñiga-Ripa A, San Román B, Zygmunt MS, Vizcaíno N, Cloeckaert A, Grilló MJ, Moriyón I, López-Goñi I. Mutants in the lipopolysaccharide of Brucella ovis are attenuated and protect against B. ovis infection in mice. Vet Res 2014; 45:72. [PMID: 25029920 PMCID: PMC4107470 DOI: 10.1186/s13567-014-0072-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 06/13/2014] [Indexed: 11/18/2022] Open
Abstract
Brucella spp. are Gram-negative bacteria that behave as facultative intracellular parasites of a variety of mammals. This genus includes smooth (S) and rough (R) species that carry S and R lipopolysaccharides (LPS), respectively. S-LPS is a virulence factor, and mutants affected in the S-LPS O-polysaccharide (R mutants), core oligosaccharide or both show attenuation. However, B. ovis is naturally R and is virulent in sheep. We studied the role of B. ovis LPS in virulence by mutating the orthologues of wadA, wadB and wadC, three genes known to encode LPS core glycosyltransferases in S brucellae. When mapped with antibodies to outer membrane proteins (Omps) and R-LPS, wadB and wadC mutants displayed defects in LPS structure and outer membrane topology but inactivation of wadA had little or no effect. Consistent with these observations, the wadB and wadC but not the wadA mutants were attenuated in mice. When tested as vaccines, the wadB and wadC mutants protected mice against B. ovis challenge. The results demonstrate that the LPS core is a structure essential for survival in vivo not only of S brucellae but also of a naturally R Brucella pathogenic species, and they confirm our previous hypothesis that the Brucella LPS core is a target for vaccine development. Since vaccine B. melitensis Rev 1 is S and thus interferes in serological testing for S brucellae, wadB mutant represents a candidate vaccine to be evaluated against B. ovis infection of sheep suitable for areas free of B. melitensis.
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Affiliation(s)
- Pedro Soler-Lloréns
- Departamento de Microbiología y Parasitología and Instituto de Salud Tropical, Universidad de Navarra, Pamplona, 31008, Spain
| | - Yolanda Gil-Ramírez
- Departamento de Microbiología y Parasitología and Instituto de Salud Tropical, Universidad de Navarra, Pamplona, 31008, Spain
| | - Ana Zabalza-Baranguá
- Instituto de Agrobiotecnología (CSIC-Universidad Pública de Navarra-Gobierno de Navarra), Pamplona, 31006, Spain
| | - Maite Iriarte
- Departamento de Microbiología y Parasitología and Instituto de Salud Tropical, Universidad de Navarra, Pamplona, 31008, Spain
| | - Raquel Conde-Álvarez
- Departamento de Microbiología y Parasitología and Instituto de Salud Tropical, Universidad de Navarra, Pamplona, 31008, Spain
| | - Amaia Zúñiga-Ripa
- Departamento de Microbiología y Parasitología and Instituto de Salud Tropical, Universidad de Navarra, Pamplona, 31008, Spain
| | - Beatriz San Román
- Instituto de Agrobiotecnología (CSIC-Universidad Pública de Navarra-Gobierno de Navarra), Pamplona, 31006, Spain
| | - Michel S Zygmunt
- INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly, F-37380, France
- Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, Tours, F-37000, France
| | - Nieves Vizcaíno
- Departamento de Microbiología y Genética, Universidad de Salamanca, and Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Axel Cloeckaert
- INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly, F-37380, France
- Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, Tours, F-37000, France
| | - María-Jesús Grilló
- Instituto de Agrobiotecnología (CSIC-Universidad Pública de Navarra-Gobierno de Navarra), Pamplona, 31006, Spain
| | - Ignacio Moriyón
- Departamento de Microbiología y Parasitología and Instituto de Salud Tropical, Universidad de Navarra, Pamplona, 31008, Spain
| | - Ignacio López-Goñi
- Departamento de Microbiología y Parasitología and Instituto de Salud Tropical, Universidad de Navarra, Pamplona, 31008, Spain
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24
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Gil-Ramírez Y, Conde-Álvarez R, Palacios-Chaves L, Zúñiga-Ripa A, Grilló MJ, Arce-Gorvel V, Hanniffy S, Moriyón I, Iriarte M. The identification of wadB, a new glycosyltransferase gene, confirms the branched structure and the role in virulence of the lipopolysaccharide core of Brucella abortus. Microb Pathog 2014; 73:53-9. [PMID: 24927935 DOI: 10.1016/j.micpath.2014.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Revised: 05/28/2014] [Accepted: 06/03/2014] [Indexed: 12/20/2022]
Abstract
Brucellosis is a worldwide extended zoonosis caused by Brucella spp. These gram-negative bacteria are not readily detected by innate immunity, a virulence-related property largely linked to their surface lipopolysaccharide (LPS). The role of the LPS lipid A and O-polysaccharide in virulence is well known. Moreover, mutation of the glycosyltransferase gene wadC of Brucella abortus, although not affecting O-polysaccharide assembly onto the lipid-A core section causes a core oligosaccharide defect that increases recognition by innate immunity. Here, we report on a second gene (wadB) encoding a LPS core glycosyltransferase not involved in the assembly of the O-polysaccharide-linked core section. As compared to wild-type B. abortus, a wadB mutant was sensitive to bactericidal peptides and non-immune serum, and was attenuated in mice and dendritic cells. These observations show that as WadC, WadB is also involved in the assembly of a branch of Brucella LPS core and support the concept that this LPS section is a virulence-related structure.
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Affiliation(s)
- Yolanda Gil-Ramírez
- Departamento de Microbiología y Parasitología e Instituto de Salud Tropical, Universidad de Navarra, 31008 Pamplona, Spain.
| | - Raquel Conde-Álvarez
- Departamento de Microbiología y Parasitología e Instituto de Salud Tropical, Universidad de Navarra, 31008 Pamplona, Spain.
| | - Leyre Palacios-Chaves
- Departamento de Microbiología y Parasitología e Instituto de Salud Tropical, Universidad de Navarra, 31008 Pamplona, Spain.
| | - Amaia Zúñiga-Ripa
- Departamento de Microbiología y Parasitología e Instituto de Salud Tropical, Universidad de Navarra, 31008 Pamplona, Spain.
| | - María-Jesús Grilló
- Instituto de Agrobiotecnología (CSIC-Universidad Pública de Navarra-Gobierno de Navarra), 31006 Pamplona, Spain.
| | - Vilma Arce-Gorvel
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University, Centre d'Immunologie de Marseille-Luminy, 13288 Marseille, France; INSERM U1104, 13288 Marseille, France; CNRS UMR7280, 13288 Marseille, France.
| | - Sean Hanniffy
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University, Centre d'Immunologie de Marseille-Luminy, 13288 Marseille, France; INSERM U1104, 13288 Marseille, France; CNRS UMR7280, 13288 Marseille, France.
| | - Ignacio Moriyón
- Departamento de Microbiología y Parasitología e Instituto de Salud Tropical, Universidad de Navarra, 31008 Pamplona, Spain.
| | - Maite Iriarte
- Departamento de Microbiología y Parasitología e Instituto de Salud Tropical, Universidad de Navarra, 31008 Pamplona, Spain.
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25
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Dieste-Pérez L, Blasco J, De Miguel M, Marín C, Barberán M, Conde-Álvarez R, Moriyón I, Muñoz P. Performance of skin tests with allergens from B. melitensis B115 and rough B. abortus mutants for diagnosing swine brucellosis. Vet Microbiol 2014; 168:161-8. [DOI: 10.1016/j.vetmic.2013.10.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 10/23/2013] [Accepted: 10/31/2013] [Indexed: 12/01/2022]
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26
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Kubler-Kielb J, Vinogradov E. Reinvestigation of the structure of Brucella O-antigens. Carbohydr Res 2013; 378:144-7. [PMID: 23664729 PMCID: PMC3744595 DOI: 10.1016/j.carres.2013.03.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Revised: 03/22/2013] [Accepted: 03/23/2013] [Indexed: 01/07/2023]
Abstract
O-Specific polysaccharides of Brucella contain two antigenic determinants, called A and M. Most of the strains express epitope A with a small amount of epitope M, whereas Brucella melitensis strain 16 M expresses longer polymer consisting mostly of M-type epitopes. Proposed explanation was that epitope A is defined by 1-2-linked homopolymer of N-formylperosamine (Rha4NFo), while epitope M is a pentasaccharide with four 2- and one 3-substituted Rha4NFo. We reinvestigated both types of structures by 2D NMR and showed that M-epitope is a tetrasaccharide, missing one of the 2-linked Rha4NFo as compared to the previously proposed structure. Polysaccharide from B. melitensis 16 M contains a fragment of 1-2-linked polymer, capped with M-type polymer. Other strains contain one or two M-type units at the non-reducing end of the 1-2-linked O-chain.
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Affiliation(s)
- Joanna Kubler-Kielb
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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27
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Ciesielski F, Griffin DC, Rittig M, Moriyón I, Bonev BB. Interactions of lipopolysaccharide with lipid membranes, raft models — A solid state NMR study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1731-42. [DOI: 10.1016/j.bbamem.2013.03.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 03/08/2013] [Accepted: 03/28/2013] [Indexed: 01/09/2023]
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28
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Dong H, Liu W, Peng X, Jing Z, Wu Q. The effects of MucR on expression of type IV secretion system, quorum sensing system and stress responses in Brucella melitensis. Vet Microbiol 2013; 166:535-42. [PMID: 23932078 DOI: 10.1016/j.vetmic.2013.06.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Revised: 06/24/2013] [Accepted: 06/25/2013] [Indexed: 01/21/2023]
Abstract
MucR is a transcriptional regulator in many bacterial pathogens and is required for virulence in mice and macrophages, resistance to stress responses, and modification of the cell envelope in Brucella spp. To determine why the mucR deleted mutant is attenuated in vivo and in vitro, we performed RNA-seq analysis using Brucella melitensis RNA obtained from B. melitensis 16M and 16MΔmucR grown under the same conditions. We found 442 differentially expressed genes; 310 were over expressed, and 132 were less expressed in 16MΔmucR. Many genes identified are involved in metabolism, cell wall/envelope biogenesis, replication, and translation. Notably, genes involved in type IV secretion system and quorum sensing system were down-regulated in 16MΔmucR. In addition, genes involved in tolerance to acid and iron-limitation were also affected and experimentally verified in this study. The effects of MucR on Brucella survival and persistence in mice and macrophages were related to type IV secretion system, quorum sensing system, and stress tolerance, which also provide added insight to the MucR regulon.
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Affiliation(s)
- Hao Dong
- Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100193, PR China
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