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Bányász B, Antal J, Dénes B. False Positives in Brucellosis Serology: Wrong Bait and Wrong Pond? Trop Med Infect Dis 2023; 8:tropicalmed8050274. [PMID: 37235322 DOI: 10.3390/tropicalmed8050274] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/07/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
This review summarizes the status of resolving the problem of false positive serologic results (FPSR) in Brucella serology, compiles our knowledge on the molecular background of the problem, and highlights some prospects for its resolution. The molecular basis of the FPSRs is reviewed through analyzing the components of the cell wall of Gram-negative bacteria, especially the surface lipopolysaccharide (LPS) with details related to brucellae. After evaluating the efforts that have been made to solve target specificity problems of serologic tests, the following conclusions can be drawn: (i) resolving the FPSR problem requires a deeper understanding than we currently possess, both of Brucella immunology and of the current serology tests; (ii) the practical solutions will be as expensive as the related research; and (iii) the root cause of FPSRs is the application of the same type of antigen (S-type LPS) in the currently approved tests. Thus, new approaches are necessary to resolve the problems stemming from FPSR. Such approaches suggested by this paper are: (i) the application of antigens from R-type bacteria; or (ii) the further development of specific brucellin-based skin tests; or (iii) the application of microbial cell-free DNA as analyte, whose approach is detailed in this paper.
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Affiliation(s)
- Borbála Bányász
- Department of Microbiology and Infectious Diseases, University of Veterinary Medicine Budapest, 1143 Budapest, Hungary
- Laboratory of Immunology, Veterinary Diagnostic Directorate, National Food Chain Safety Office, 1143 Budapest, Hungary
| | - József Antal
- Omixon Biocomputing Ltd., 1117 Budapest, Hungary
| | - Béla Dénes
- Department of Microbiology and Infectious Diseases, University of Veterinary Medicine Budapest, 1143 Budapest, Hungary
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2
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Ouahrani-Bettache S, Jiménez De Bagüés MP, De La Garza J, Freddi L, Bueso JP, Lyonnais S, Al Dahouk S, De Biase D, Köhler S, Occhialini A. Lethality of Brucella microti in a murine model of infection depends on the wbkE gene involved in O-polysaccharide synthesis. Virulence 2020; 10:868-878. [PMID: 31635539 PMCID: PMC6844557 DOI: 10.1080/21505594.2019.1682762] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Brucella microti was isolated a decade ago from wildlife and soil in Europe. Compared to the classical Brucella species, it exhibits atypical virulence properties such as increased growth in human and murine macrophages and lethality in experimentally infected mice. A spontaneous rough (R) mutant strain, derived from the smooth reference strain CCM4915T, showed increased macrophage colonization and was non-lethal in murine infections. Whole-genome sequencing and construction of an isogenic mutant of B. microti and Brucella suis 1330 revealed that the R-phenotype was due to a deletion in a single gene, namely wbkE (BMI_I539), encoding a putative glycosyltransferase involved in lipopolysaccharide (LPS) O-polysaccharide biosynthesis. Complementation of the R-strains with the wbkE gene restored the smooth phenotype and the ability of B. microti to kill infected mice. LPS with an intact O-polysaccharide is therefore essential for lethal B. microti infections in the murine model, demonstrating its importance in pathogenesis.
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Affiliation(s)
| | - María P Jiménez De Bagüés
- Unidad de Tecnología en Producción y Sanidad Animal, Centro de Investigación y Tecnología Agroalimentaria, Instituto Agroalimentario de Aragón, Universidad de Zaragoza, Zaragoza, Spain
| | | | - Luca Freddi
- IRIM, CNRS, University Montpellier, INSERM, Montpellier, France
| | - Juan P Bueso
- Laboratorio Agroalimentario, Gobierno de Aragón, Zaragoza, Spain
| | | | - Sascha Al Dahouk
- Department of Biological Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Daniela De Biase
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Laboratory affiliated to the Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Latina, Italy
| | - Stephan Köhler
- IRIM, CNRS, University Montpellier, INSERM, Montpellier, France
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3
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Colombo C, Pitirollo O, Lay L. Recent Advances in the Synthesis of Glycoconjugates for Vaccine Development. Molecules 2018; 23:molecules23071712. [PMID: 30011851 PMCID: PMC6099631 DOI: 10.3390/molecules23071712] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/09/2018] [Accepted: 07/11/2018] [Indexed: 12/25/2022] Open
Abstract
During the last decade there has been a growing interest in glycoimmunology, a relatively new research field dealing with the specific interactions of carbohydrates with the immune system. Pathogens’ cell surfaces are covered by a thick layer of oligo- and polysaccharides that are crucial virulence factors, as they mediate receptors binding on host cells for initial adhesion and organism invasion. Since in most cases these saccharide structures are uniquely exposed on the pathogen surface, they represent attractive targets for vaccine design. Polysaccharides isolated from cell walls of microorganisms and chemically conjugated to immunogenic proteins have been used as antigens for vaccine development for a range of infectious diseases. However, several challenges are associated with carbohydrate antigens purified from natural sources, such as their difficult characterization and heterogeneous composition. Consequently, glycoconjugates with chemically well-defined structures, that are able to confer highly reproducible biological properties and a better safety profile, are at the forefront of vaccine development. Following on from our previous review on the subject, in the present account we specifically focus on the most recent advances in the synthesis and preliminary immunological evaluation of next generation glycoconjugate vaccines designed to target bacterial and fungal infections that have been reported in the literature since 2011.
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Affiliation(s)
- Cinzia Colombo
- Dipartimento di Chimica, Universita' degli Studi di Milano, via Golgi 19, 20133 Milano, Italy.
| | - Olimpia Pitirollo
- Dipartimento di Chimica, Universita' degli Studi di Milano, via Golgi 19, 20133 Milano, Italy.
| | - Luigi Lay
- Dipartimento di Chimica, Universita' degli Studi di Milano, via Golgi 19, 20133 Milano, Italy.
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Vergnaud G, Hauck Y, Christiany D, Daoud B, Pourcel C, Jacques I, Cloeckaert A, Zygmunt MS. Genotypic Expansion Within the Population Structure of Classical Brucella Species Revealed by MLVA16 Typing of 1404 Brucella Isolates From Different Animal and Geographic Origins, 1974-2006. Front Microbiol 2018; 9:1545. [PMID: 30050522 PMCID: PMC6052141 DOI: 10.3389/fmicb.2018.01545] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 06/21/2018] [Indexed: 11/22/2022] Open
Abstract
Previous studies have shown the usefulness of MLVA16 as a rapid molecular identification and classification method for Brucella species and biovars including recently described novel Brucella species from wildlife. Most studies were conducted on a limited number of strains from limited geographic/host origins. The objective of this study was to assess genetic diversity of Brucella spp. by MLVA16 on a larger scale. Thus, 1404 animal or human isolates collected from all parts of the world over a period of 32 years (1974-2006) were investigated. Selection of the 1404 strains was done among the approximately 4000 strains collection of the BCCN (Brucella Culture Collection Nouzilly), based on classical biotyping and on the animal/human/geographic origin over the time period considered. MLVA16 was performed on extracted DNAs using high throughput capillary electrophoresis. The 16 loci were amplified in four multiplex PCR reactions. This large scale study firstly confirmed the accuracy of MLVA16 typing for Brucella species and biovar identification and its congruence with the recently described Extended Multilocus Sequence Analysis. In addition, it allowed identifying novel MLVA11 (based upon 11 slowly evolving VNTRs) genotypes representing an increase of 15% relative to the previously known Brucella MLVA11 genotypes. Cluster analysis showed that among the MLVA16 genotypes some were genetically more distant from the major classical clades. For example new major clusters of B. abortus biovar 3 isolated from cattle in Sub-Saharan Africa were identified. For other classical species and biovars this study indicated also genotypic expansion within the population structure of classical Brucella species. MLVA proves to be a powerful tool to rapidly assess genetic diversity of bacterial populations on a large scale, as here on a large collection of strains of the genomically homogeneous genus Brucella. The highly discriminatory power of MLVA appears of particular interest as a first step for selection of Brucella strains for whole-genome sequencing. The MLVA data of this study were added to the public Brucella MLVA database at http://microbesgenotyping.i2bc.paris-saclay.fr. Current version Brucella_4_3 comprises typing data from more than 5000 strains including in silico data analysis of public whole genome sequence datasets.
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Affiliation(s)
- Gilles Vergnaud
- Institute for Integrative Biology of the Cell, CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Yolande Hauck
- Institute for Integrative Biology of the Cell, CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - David Christiany
- Institute for Integrative Biology of the Cell, CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Brendan Daoud
- Institute for Integrative Biology of the Cell, CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Christine Pourcel
- Institute for Integrative Biology of the Cell, CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Isabelle Jacques
- ISP, INRA, Université François Rabelais de Tours, UMR 1282, Nouzilly, France.,IUT de Tours, Tours, France
| | - Axel Cloeckaert
- ISP, INRA, Université François Rabelais de Tours, UMR 1282, Nouzilly, France
| | - Michel S Zygmunt
- ISP, INRA, Université François Rabelais de Tours, UMR 1282, Nouzilly, France
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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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Mandal SS, Ganesh NV, Sadowska JM, Bundle DR. Synthetic glycoconjugates characterize the fine specificity of Brucella A and M monoclonal antibodies. Org Biomol Chem 2018; 15:3874-3883. [PMID: 28317992 DOI: 10.1039/c7ob00445a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dominant cell wall antigen of Brucella bacteria is the O-polysaccharide component of the smooth lipopolysaccharide. Infection by various Brucella biovars causes abortions and infertility in a wide range of domestic and wild animals and debilitating disease in humans. Diagnosis relies on the detection of antibodies to the A and M antigens expressed in the O-polysaccharide. This molecule is a homopolymer of the rare monosaccharide, 4-formamido-4,6-dideoxy-d-mannopyranose (Rha4NFo). The A epitope is created by a uniform α1,2 linked internal polymeric sequence capped by a distinct tetrasaccharide sequence defining the M antigen. Unique oligosaccharides only available by chemical synthesis and conjugated via reducing and non-reducing residues to bovine serum albumin have revealed the structural basis of the fine specificity that allows the discrimination of these closely related A and M epitopes. All three M specific monoclonal antibodies (mAbs) are inferred to possess groove type binding sites open at each end, and recognize an α1,3 linked Rha4NFo disaccharide as a part of a trisaccharide epitope, which in two mAbs includes the terminal Rha4NFo residue. The binding site of one of these antibodies is sufficiently large to engage up to six Rha4NFo residues and involves weak recognition of α1,2 linked Rha4NFo residues. The third mAb binds an internal trisaccharide epitope of the M tetrasaccharide. Two A specific mAbs also possess groove type binding sites that accommodate six and four α1,2 linked Rha4NFo residues.
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Abstract
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Brucellosis is a serious zoonotic bacterial disease that is ranked
by the World Health Organization among the top seven “neglected
zoonoses” that threaten human health and cause poverty. It
is a costly, highly contagious disease that affects ruminants, cattle,
sheep, goats, and other productive animals such as pigs. Symptoms
include abortions, infertility, decreased milk production, weight
loss, and lameness. Brucellosis is also the most common bacterial
disease that is transmitted from animals to humans, with approximately
500 000 new human cases each year. Detection and slaughter
of infected animals is required to eradicate the disease, as vaccination
alone is currently insufficient. However, as the most protective vaccines
compromise serodiagnosis, this creates policy dilemmas, and these
often result in the failure of eradication and control programs. Detection
of antibodies to the Brucella bacterial
cell wall O-polysaccharide (OPS) component of smooth lipopolysaccharide
is used in diagnosis of this disease, and the same molecule contributes
important protective efficacy to currently deployed veterinary whole-cell
vaccines. This has set up a long-standing paradox that while Brucella OPS confers protective efficacy to vaccines,
its presence results in similar antibody profiles in infected and
vaccinated animals. Consequently, differentiation of infected from
vaccinated animals (DIVA) is not possible, and this limits efforts
to combat the disease. Recent clarification of the chemical structure
of Brucella OPS as a block copolymer
of two oligosaccharide sequences has provided an opportunity to utilize
unique oligosaccharides only available via chemical synthesis in serodiagnostic
tests for the disease. These oligosaccharides show excellent sensitivity
and specificity compared with the native polymer used in current commercial
tests and have the added advantage of assisting discrimination between
brucellosis and infections caused by several bacteria with OPS that
share some structural features with those of Brucella. During synthesis and immunochemical evaluation of these synthetic
antigens, it became apparent that an opportunity existed to create
a polysaccharide–protein conjugate vaccine that would not create
antibodies that give false positive results in diagnostic tests for
infection. This objective was reduced to practice, and immunization
of mice showed that antibodies to the Brucella A antigen could be developed without reacting in a diagnostic test
based on the M antigen. A conjugate vaccine of this type could readily
be developed for use in humans and animals. However, as chemical methods
advance and modern methods of bacterial engineering mature, it is
expected that the principles elucidated by these studies could be
applied to the development of an inexpensive and cost-effective vaccine
to combat endemic brucellosis in animals.
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Affiliation(s)
- David R. Bundle
- Department
of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - John McGiven
- FAO/WHO Collaborating Centre for Brucellosis, OIE Brucellosis Reference Laboratory, Department of Bacteriology, Animal & Plant Health Agency, Woodham Lane, Addlestone, Surrey KT15 3NB, United Kingdom
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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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