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Zhai LN, Zhao Y, Song XL, Qin TT, Zhang ZJ, Wang JZ, Sui CY, Zhang LL, Lv M, Hu LF, Zhou DS, Fang TY, Yang WH, Wang YC. Inhalable vaccine of bacterial culture supernatant extract mediates protection against fatal pulmonary anthrax. Emerg Microbes Infect 2023; 12:2191741. [PMID: 36920800 PMCID: PMC10071900 DOI: 10.1080/22221751.2023.2191741] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
AbstractPulmonary anthrax is the most fatal clinical form of anthrax and currently available injectable vaccines do not provide adequate protection against it. Hence, next-generation vaccines that effectively induce immunity against pulmonary anthrax are urgently needed. In the present study, we prepared an attenuated and low protease activity Bacillus anthracis strain A16R-5.1 by deleting five of its extracellular protease activity-associated genes and its lef gene through the CRISPR-Cas9 genome editing system. This mutant strain was then used to formulate a lethal toxin (LeTx)-free culture supernatant extract (CSE) anthrax vaccine,of which half was protective antigen (PA). We generated liquid, powder, and powder reconstituted formulations that could be delivered by aerosolized intratracheal inoculation. All of them induced strong humoral, cellular, and mucosal immune responses. The vaccines also produced LeTx neutralizing antibodies and conferred full protection against the lethal aerosol challenges of B. anthracis Pasteur II spores in mice. Compared to the recombinant PA vaccine, the CSE anthrax vaccine with equal PA content provided superior immunoprotection against pulmonary anthrax. The preceding results suggest that the CSE anthrax vaccine developed herein is suitable and scalable for use in inhalational immunization against pulmonary anthrax.
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Affiliation(s)
- Li-Na Zhai
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Yue Zhao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.,Basic medical college, Guizhou Medical University, Guizhou 550004, China
| | - Xiao-Lin Song
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Tong-Tong Qin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Zhi-Jun Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Jia-Zhen Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Cheng-Yu Sui
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Li-Li Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Meng Lv
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Ling-Fei Hu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Dong-Sheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Tong-Yu Fang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Wen-Hui Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Yan-Chun Wang
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
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2
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Hoelzgen F, Zalk R, Alcalay R, Cohen-Schwartz S, Garau G, Shahar A, Mazor O, Frank GA. Neutralization of the anthrax toxin by antibody-mediated stapling of its membrane-penetrating loop. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2021; 77:1197-1205. [PMID: 34473089 DOI: 10.1107/s2059798321007816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/30/2021] [Indexed: 12/15/2022]
Abstract
Anthrax infection is associated with severe illness and high mortality. Protective antigen (PA) is the central component of the anthrax toxin, which is one of two major virulence factors of Bacillus anthracis, the causative agent of anthrax disease. Upon endocytosis, PA opens a pore in the membranes of endosomes, through which the cytotoxic enzymes of the toxin are extruded. The PA pore is formed by a cooperative conformational change in which the membrane-penetrating loops of PA associate, forming a hydrophobic rim that pierces the membrane. Due to its crucial role in anthrax progression, PA is an important target for monoclonal antibody-based therapy. cAb29 is a highly effective neutralizing antibody against PA. Here, the cryo-EM structure of PA in complex with the Fab portion of cAb29 was determined. It was found that cAb29 neutralizes the toxin by clamping the membrane-penetrating loop of PA to the static surface-exposed loop of the D3 domain of the same subunit, thereby preventing pore formation. These results provide the structural basis for the antibody-based neutralization of PA and bring into focus the membrane-penetrating loop of PA as a target for the development of better anti-anthrax vaccines.
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Affiliation(s)
- F Hoelzgen
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 8410501, Israel
| | - R Zalk
- Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer Sheva 8410501, Israel
| | - R Alcalay
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - S Cohen-Schwartz
- The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer Sheva 8410501, Israel
| | - G Garau
- Biostructures Lab, IIT@NEST - Istituto Italiano di Tecnologia, Piazza San Silvestro 12, 56124 Pisa, Italy
| | - A Shahar
- Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer Sheva 8410501, Israel
| | - O Mazor
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - G A Frank
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 8410501, Israel
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3
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Zaide G, Elia U, Cohen-Gihon I, Israeli M, Rotem S, Israeli O, Ehrlich S, Cohen H, Lazar S, Beth-Din A, Shafferman A, Zvi A, Cohen O, Chitlaru T. Comparative Analysis of the Global Transcriptomic Response to Oxidative Stress of Bacillus anthracis htrA-Disrupted and Parental Wild Type Strains. Microorganisms 2020; 8:microorganisms8121896. [PMID: 33265965 PMCID: PMC7760947 DOI: 10.3390/microorganisms8121896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 11/26/2020] [Accepted: 11/27/2020] [Indexed: 12/30/2022] Open
Abstract
We previously demonstrated that the HtrA (High Temperature Requirement A) protease/chaperone active in the quality control of protein synthesis, represents an important virulence determinant of Bacillus anthracis. Virulence attenuation of htrA-disrupted Bacillus anthracis strains was attributed to susceptibility of ΔhtrA strains to stress insults, as evidenced by affected growth under various stress conditions. Here, we report a comparative RNA-seq transcriptomic study generating a database of differentially expressed genes in the B. anthracishtrA-disrupted and wild type parental strains under oxidative stress. The study demonstrates that, apart from protease and chaperone activities, HtrA exerts a regulatory role influencing expression of more than 1000 genes under stress. Functional analysis of groups or individual genes exhibiting strain-specific modulation, evidenced (i) massive downregulation in the ΔhtrA and upregulation in the WT strains of various transcriptional regulators, (ii) downregulation of translation processes in the WT strain, and (iii) downregulation of metal ion binding functions and upregulation of sporulation-associated functions in the ΔhtrA strain. These modulated functions are extensively discussed. Fifteen genes uniquely upregulated in the wild type strain were further interrogated for their modulation in response to other stress regimens. Overexpression of one of these genes, encoding for MazG (a nucleoside triphosphate pyrophosphohydrolase involved in various stress responses in other bacteria), in the ΔhtrA strain resulted in partial alleviation of the H2O2-sensitive phenotype.
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4
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Israeli M, Elia U, Rotem S, Cohen H, Tidhar A, Bercovich-Kinori A, Cohen O, Chitlaru T. Distinct Contribution of the HtrA Protease and PDZ Domains to Its Function in Stress Resilience and Virulence of Bacillus anthracis. Front Microbiol 2019; 10:255. [PMID: 30833938 PMCID: PMC6387919 DOI: 10.3389/fmicb.2019.00255] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 01/30/2019] [Indexed: 12/19/2022] Open
Abstract
Anthrax is a lethal disease caused by the Gram-positive spore-producing bacterium Bacillus anthracis. We previously demonstrated that disruption of htrA gene, encoding the chaperone/protease HtrABA (High Temperature Requirement A of B. anthracis) results in significant virulence attenuation, despite unaffected ability of ΔhtrA strains (in which the htrA gene was deleted) to synthesize the key anthrax virulence factors: the exotoxins and capsule. B. anthracis ΔhtrA strains exhibited increased sensitivity to stress regimens as well as silencing of the secreted starvation-associated Neutral Protease A (NprA) and down-modulation of the bacterial S-layer. The virulence attenuation associated with disruption of the htrA gene was suggested to reflect the susceptibility of ΔhtrA mutated strains to stress insults encountered in the host indicating that HtrABA represents an important B. anthracis pathogenesis determinant. As all HtrA serine proteases, HtrABA exhibits a protease catalytic domain and a PDZ domain. In the present study we interrogated the relative impact of the proteolytic activity (mediated by the protease domain) and the PDZ domain (presumably necessary for the chaperone activity and/or interaction with substrates) on manifestation of phenotypic characteristics mediated by HtrABA. By inspecting the phenotype exhibited by ΔhtrA strains trans-complemented with either a wild-type, truncated (ΔPDZ), or non-proteolytic form (mutated in the catalytic serine residue) of HtrABA, as well as strains exhibiting modified chromosomal alleles, it is shown that (i) the proteolytic activity of HtrABA is essential for its N-terminal autolysis and subsequent release into the extracellular milieu, while the PDZ domain was dispensable for this process, (ii) the PDZ domain appeared to be dispensable for most of the functions related to stress resilience as well as involvement of HtrABA in assembly of the bacterial S-layer, (iii) conversely, the proteolytic activity but not the PDZ domain, appeared to be dispensable for the role of HtrABA in mediating up-regulation of the extracellular protease NprA under starvation stress, and finally (iv) in a murine model of anthrax, the HtrABA PDZ domain, was dispensable for manifestation of B. anthracis virulence. The unexpected dispensability of the PDZ domain may represent a unique characteristic of HtrABA amongst bacterial serine proteases of the HtrA family.
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Affiliation(s)
- Ma'ayan Israeli
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Uri Elia
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Shahar Rotem
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Hila Cohen
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Avital Tidhar
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Adi Bercovich-Kinori
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Ofer Cohen
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Theodor Chitlaru
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness Ziona, Israel
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5
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Carlson CJ, Getz WM, Kausrud KL, Cizauskas CA, Blackburn JK, Bustos Carrillo FA, Colwell R, Easterday WR, Ganz HH, Kamath PL, Økstad OA, Turner WC, Kolstø AB, Stenseth NC. Spores and soil from six sides: interdisciplinarity and the environmental biology of anthrax (Bacillus anthracis). Biol Rev Camb Philos Soc 2018; 93:1813-1831. [PMID: 29732670 DOI: 10.1111/brv.12420] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Revised: 03/27/2018] [Accepted: 04/03/2018] [Indexed: 12/11/2022]
Abstract
Environmentally transmitted diseases are comparatively poorly understood and managed, and their ecology is particularly understudied. Here we identify challenges of studying environmental transmission and persistence with a six-sided interdisciplinary review of the biology of anthrax (Bacillus anthracis). Anthrax is a zoonotic disease capable of maintaining infectious spore banks in soil for decades (or even potentially centuries), and the mechanisms of its environmental persistence have been the topic of significant research and controversy. Where anthrax is endemic, it plays an important ecological role, shaping the dynamics of entire herbivore communities. The complex eco-epidemiology of anthrax, and the mysterious biology of Bacillus anthracis during its environmental stage, have necessitated an interdisciplinary approach to pathogen research. Here, we illustrate different disciplinary perspectives through key advances made by researchers working in Etosha National Park, a long-term ecological research site in Namibia that has exemplified the complexities of the enzootic process of anthrax over decades of surveillance. In Etosha, the role of scavengers and alternative routes (waterborne transmission and flies) has proved unimportant relative to the long-term persistence of anthrax spores in soil and their infection of herbivore hosts. Carcass deposition facilitates green-ups of vegetation to attract herbivores, potentially facilitated by the role of anthrax spores in the rhizosphere. The underlying seasonal pattern of vegetation, and herbivores' immune and behavioural responses to anthrax risk, interact to produce regular 'anthrax seasons' that appear to be a stable feature of the Etosha ecosystem. Through the lens of microbiologists, geneticists, immunologists, ecologists, epidemiologists, and clinicians, we discuss how anthrax dynamics are shaped at the smallest scale by population genetics and interactions within the bacterial communities up to the broadest scales of ecosystem structure. We illustrate the benefits and challenges of this interdisciplinary approach to disease ecology, and suggest ways anthrax might offer insights into the biology of other important pathogens. Bacillus anthracis, and the more recently emerged Bacillus cereus biovar anthracis, share key features with other environmentally transmitted pathogens, including several zoonoses and panzootics of special interest for global health and conservation efforts. Understanding the dynamics of anthrax, and developing interdisciplinary research programs that explore environmental persistence, is a critical step forward for understanding these emerging threats.
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Affiliation(s)
- Colin J Carlson
- National Socio-Environmental Synthesis Center (SESYNC), University of Maryland, Annapolis, MD 21401, U.S.A.,Department of Biology, Georgetown University, Washington, DC 20057, U.S.A
| | - Wayne M Getz
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, U.S.A.,School of Mathematical Sciences, University of KwaZulu-Natal, PB X 54001, Durban 4000, South Africa
| | - Kyrre L Kausrud
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, N-0316, Oslo, Norway
| | - Carrie A Cizauskas
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, U.S.A
| | - Jason K Blackburn
- Spatial Epidemiology & Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, U.S.A.,Emerging Pathogens Institute, University of Florida, Gainesville, FL, U.S.A
| | - Fausto A Bustos Carrillo
- Department of Epidemiology & Department of Biostatistics, School of Public Health, University of California, Berkeley, CA 94720-7360, U.S.A
| | - Rita Colwell
- CosmosID Inc., Rockville, MD 20850, U.S.A.,Center for Bioinformatics and Computational Biology, University of Maryland Institute for Advanced Computer Studies, University of Maryland, College Park, MD 20742, U.S.A.,Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, U.S.A
| | - W Ryan Easterday
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, N-0316, Oslo, Norway
| | - Holly H Ganz
- UC Davis Genome Center, University of California, Davis, CA 95616, U.S.A
| | - Pauline L Kamath
- School of Food and Agriculture, University of Maine, Orono, ME 04469, U.S.A
| | - Ole A Økstad
- Centre for Integrative Microbial Evolution and Section for Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, N-0316, Oslo, Norway
| | - Wendy C Turner
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, U.S.A
| | - Anne-Brit Kolstø
- Centre for Integrative Microbial Evolution and Section for Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, N-0316, Oslo, Norway
| | - Nils C Stenseth
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, N-0316, Oslo, Norway
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6
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Chitlaru T, Israeli M, Rotem S, Elia U, Bar-Haim E, Ehrlich S, Cohen O, Shafferman A. A novel live attenuated anthrax spore vaccine based on an acapsular Bacillus anthracis Sterne strain with mutations in the htrA, lef and cya genes. Vaccine 2017; 35:6030-6040. [DOI: 10.1016/j.vaccine.2017.03.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 01/24/2017] [Accepted: 03/08/2017] [Indexed: 02/06/2023]
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Koehler SM, Buyuk F, Celebi O, Demiraslan H, Doganay M, Sahin M, Moehring J, Ndumnego OC, Otlu S, van Heerden H, Beyer W. Protection of farm goats by combinations of recombinant peptides and formalin inactivated spores from a lethal Bacillus anthracis challenge under field conditions. BMC Vet Res 2017; 13:220. [PMID: 28701192 PMCID: PMC5508662 DOI: 10.1186/s12917-017-1140-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 07/04/2017] [Indexed: 11/30/2022] Open
Abstract
Background Bacillus (B.) anthracis, the causal agent of anthrax, is effectively controlled by the Sterne live spore vaccine (34F2) in animals. However, live spore vaccines are not suitable for simultaneous vaccination and antibiotic treatment of animals being at risk of infection in an outbreak situation. Non-living vaccines could close this gap. Results In this study a combination of recombinant protective antigen and recombinant Bacillus collagen-like antigen (rBclA) with or without formalin inactivated spores (FIS), targeted at raising an immune response against both the toxins and the spore of B. anthracis, was tested for immunogenicity and protectiveness in goats. Two groups of goats received from local farmers of the Kars region of Turkey were immunized thrice in three weeks intervals and challenged together with non-vaccinated controls with virulent B. anthracis, four weeks after last immunization. In spite of low or none measurable toxin neutralizing antibodies and a surprisingly low immune response to the rBclA, 80% of the goats receiving the complete vaccine were protected against a lethal challenge. Moreover, the course of antibody responses indicates that a two-step vaccination schedule could be sufficient for protection. Conclusion The combination of recombinant protein antigens and FIS induces a protective immune response in goats. The non-living nature of this vaccine would allow for a concomitant antibiotic treatment and vaccination procedure. Further studies should clarify how this vaccine candidate performs in a post infection scenario controlled by antibiotics. Electronic supplementary material The online version of this article (doi:10.1186/s12917-017-1140-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Susanne M Koehler
- Department of Infectiology and Animal Hygiene, University of Hohenheim, Institute of Animal Science, 70593, Stuttgart, Germany.,Robert-Koch-Institut, 13353, Berlin, Germany
| | - Fatih Buyuk
- Faculty of Veterinary Medicine, Department of Microbiology, Kafkas University, 36300, Kars, Turkey
| | - Ozgur Celebi
- Faculty of Veterinary Medicine, Department of Microbiology, Kafkas University, 36300, Kars, Turkey
| | - Hayati Demiraslan
- Faculty of Medicine, Department of Infectious Diseases, Erciyes University, 38039, Kayseri, Turkey
| | - Mehmet Doganay
- Faculty of Medicine, Department of Infectious Diseases, Erciyes University, 38039, Kayseri, Turkey
| | - Mitat Sahin
- Faculty of Veterinary Medicine, Department of Microbiology, Kafkas University, 36300, Kars, Turkey
| | - Jens Moehring
- Institute for Crop Science, University of Hohenheim, Biostatistical Unit, 70593, Stuttgart, Germany
| | - Okechukwu C Ndumnego
- Department of Veterinary Tropical Diseases, University of Pretoria, Onderstepoort, 0110, South Africa.,Africa Health Research Institute, Durban, 4013, South Africa
| | - Salih Otlu
- Faculty of Veterinary Medicine, Department of Microbiology, Kafkas University, 36300, Kars, Turkey
| | - Henriette van Heerden
- Department of Veterinary Tropical Diseases, University of Pretoria, Onderstepoort, 0110, South Africa
| | - Wolfgang Beyer
- Department of Infectiology and Animal Hygiene, University of Hohenheim, Institute of Animal Science, 70593, Stuttgart, Germany.
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8
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Gulseren D, Süzük-Yıldız S, Çelebi B, Kılıç S. Evaluation of clinical and serological findings for diagnosis of cutaneous anthrax infection after an outbreak. Cutan Ocul Toxicol 2017; 36:289-293. [PMID: 28076993 DOI: 10.1080/15569527.2017.1281288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE Anthrax, caused by the bacterium Bacillus anthracis, is one of the oldest documented infectious diseases in both livestock and humans. We aimed to evaluate clinical findings and risk factors of patients with cutaneous anthrax infection and report anti-lethal factor (LF) IgG and anti-protective antigen (PA) IgG titers in the serologic diagnosis of disease. METHODS In this study, serum samples of 18 cutaneous anthrax patients were collected and anti-LF IgG and anti-PA IgG titers were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS Twelve (67%) males and 6 (33%) females, with a mean age of 36.06 ± 16.58 years were included in the study. Risk factors identified in the patient population studied were slaughtering (28%), flaying (56%), chopping meat (67%), burying diseased animal corpses (17%) and milking (6%) livestock. Black eschar formation (94%), pruritus (78%) and painful lymphadenopathy (61%) were first three common clinical signs and symptoms, respectively. Fourteen (78%) patients produced a positive IgG response against PA, 11 (61%) patients produced against LF. Three (17%) patients had no response to either antigen. CONCLUSIONS A detailed history of contact with sick animals or animal products along with clinical findings should be taken at the first step for the diagnosis of cutaneous anthrax infection. Serologic detection of anti-LF IgG and anti-PA IgG with ELISA may be useful auxillary method for establishing the diagnosis.
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Affiliation(s)
- Duygu Gulseren
- a Department of Dermatology , Ankara Polatlı State Hospital , Ankara , Turkey and
| | - Serap Süzük-Yıldız
- b Department of Microbiology Reference Laboratory , Public Health Institution of Turkey , Ankara , Turkey
| | - Bekir Çelebi
- b Department of Microbiology Reference Laboratory , Public Health Institution of Turkey , Ankara , Turkey
| | - Selçuk Kılıç
- b Department of Microbiology Reference Laboratory , Public Health Institution of Turkey , Ankara , Turkey
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9
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Mechaly A, Marx S, Levy O, Yitzhaki S, Fisher M. Highly Stable Lyophilized Homogeneous Bead-Based Immunoassays for On-Site Detection of Bio Warfare Agents from Complex Matrices. Anal Chem 2016; 88:6283-91. [PMID: 27253489 DOI: 10.1021/acs.analchem.6b00362] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
This study shows the development of dry, highly stable immunoassays for the detection of bio warfare agents in complex matrices. Thermal stability was achieved by the lyophilization of the complete, homogeneous, bead-based immunoassay in a special stabilizing buffer, resulting in a ready-to-use, simple assay, which exhibited long shelf and high-temperature endurance (up to 1 week at 100 °C). The developed methodology was successfully implemented for the preservation of time-resolved fluorescence, Alexa-fluorophores, and horse radish peroxidase-based bead assays, enabling multiplexed detection. The multiplexed assay was successfully implemented for the detection of Bacillus anthracis, botulinum B, and tularemia in complex matrices.
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Affiliation(s)
- Adva Mechaly
- Department of Infectious Diseases and ‡Department of Physical Chemistry, IIBR , Ness-Ziona 74100, Israel
| | - Sharon Marx
- Department of Infectious Diseases and ‡Department of Physical Chemistry, IIBR , Ness-Ziona 74100, Israel
| | - Orly Levy
- Department of Infectious Diseases and ‡Department of Physical Chemistry, IIBR , Ness-Ziona 74100, Israel
| | - Shmuel Yitzhaki
- Department of Infectious Diseases and ‡Department of Physical Chemistry, IIBR , Ness-Ziona 74100, Israel
| | - Morly Fisher
- Department of Infectious Diseases and ‡Department of Physical Chemistry, IIBR , Ness-Ziona 74100, Israel
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10
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Cohen N, Zahavy E, Zichel R, Fisher M. An internal standard approach for homogeneous TR-FRET immunoassays facilitates the detection of bacteria, biomarkers, and toxins in complex matrices. Anal Bioanal Chem 2016; 408:5179-88. [PMID: 27236318 DOI: 10.1007/s00216-016-9602-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 04/13/2016] [Accepted: 04/25/2016] [Indexed: 10/21/2022]
Abstract
The recent development of a homogeneous time-resolved Förster resonance energy transfer (TR-FRET) immunoassay enables one-step, rapid (minutes), and direct detection compared to the multistep, time-consuming (hours), heterogeneous ELISA-type immunoassays. The use of the time-resolved effect of a donor lanthanide complex with a delay time of microseconds and large Stokes shift enables the separation of positive signals from the background autofluorescence of the sample. However, this study shows that the sample matrices directly interfere with donor fluorescence and that interference cannot be eliminated by time-resolved settings alone. Moreover, the reduction in donor emission did not appear to be equivalent to the reduction in acceptor emission, resulting in incorrect FRET signal measurements. To overcome this limitation, an internal standard approach was developed using an isotype control antibody. This new approach was used to develop TR-FRET assays for rapid detection (15-30 min) of Bacillus anthracis spores and botulinum toxin (type E) in beverages, which are major concerns in bioterrorism involving deliberate food contamination. Additionally, we demonstrate the detection of B. anthracis-secreted protective antigen (PA) and the Yersinia pestis-secreted markers F1 and LcrV in blood cultures, which are early markers of bacteremia in infected hosts following a possible bioterror attack. The use of an internal standard enables the calculation of correct ΔF values without the need for an external standard. Thus, the use of the internal standard approach in homogeneous immunoassays facilitates the examination of any sample regardless of its origin, and therefore expands the applicability of TR-FRET assays for complex matrices.
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Affiliation(s)
- Noam Cohen
- Department of Biotechnology, Israel Institute for Biological Research, Ness-Ziona, 74100, Israel
| | - Eran Zahavy
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona, 74100, Israel
| | - Ran Zichel
- Department of Biotechnology, Israel Institute for Biological Research, Ness-Ziona, 74100, Israel
| | - Morly Fisher
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona, 74100, Israel.
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11
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Ghosh N, Gunti D, Lukka H, Reddy BR, Padmaja J, Goel AK. Development & validation of a quantitative anti-protective antigen IgG enzyme linked immunosorbent assay for serodiagnosis of cutaneous anthrax. Indian J Med Res 2016; 142:196-204. [PMID: 26354217 PMCID: PMC4613441 DOI: 10.4103/0971-5916.164258] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Background & objectives: Anthrax caused by Bacillus anthracis is primarily a disease of herbivorous animals, although several mammals are vulnerable to it. ELISA is the most widely accepted serodiagnostic assay for large scale surveillance of cutaneous anthrax. The aims of this study were to develop and evaluate a quantitative ELISA for determination of IgG antibodies against B. anthracis protective antigen (PA) in human cutaneous anthrax cases. Methods: Quantitative ELISA was developed using the recombinant PA for coating and standard reference serum AVR801 for quantification. A total of 116 human test and control serum samples were used in the study. The assay was evaluated for its precision, accuracy and linearity. Results: The minimum detection limit and lower limit of quantification of the assay for anti-PA IgG were 3.2 and 4 µg/ml, respectively. The serum samples collected from the anthrax infected patients were found to have anti-PA IgG concentrations of 5.2 to 166.3 µg/ml. The intra-assay precision per cent CV within an assay and within an operator ranged from 0.99 to 7.4 per cent and 1.7 to 3.9 per cent, respectively. The accuracy of the assay was high with a per cent error of 6.5 - 24.1 per cent. The described assay was found to be linear between the range of 4 to 80 ng/ml (R2=0.9982; slope=0.9186; intercept = 0.1108). Interpretation & conclusions: The results suggested that the developed assay could be a useful tool for quantification of anti-PA IgG response in human after anthrax infection or vaccination.
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Affiliation(s)
| | | | | | | | | | - A K Goel
- Biotechnology Division, Defence Research & Development Establishment, Gwalior, India
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12
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The Exosporium Layer of Bacterial Spores: a Connection to the Environment and the Infected Host. Microbiol Mol Biol Rev 2016; 79:437-57. [PMID: 26512126 DOI: 10.1128/mmbr.00050-15] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Much of what we know regarding bacterial spore structure and function has been learned from studies of the genetically well-characterized bacterium Bacillus subtilis. Molecular aspects of spore structure, assembly, and function are well defined. However, certain bacteria produce spores with an outer spore layer, the exosporium, which is not present on B. subtilis spores. Our understanding of the composition and biological functions of the exosporium layer is much more limited than that of other aspects of the spore. Because the bacterial spore surface is important for the spore's interactions with the environment, as well as being the site of interaction of the spore with the host's innate immune system in the case of spore-forming bacterial pathogens, the exosporium is worthy of continued investigation. Recent exosporium studies have focused largely on members of the Bacillus cereus family, principally Bacillus anthracis and Bacillus cereus. Our understanding of the composition of the exosporium, the pathway of its assembly, and its role in spore biology is now coming into sharper focus. This review expands on a 2007 review of spore surface layers which provided an excellent conceptual framework of exosporium structure and function (A. O. Henriques and C. P. Moran, Jr., Annu Rev Microbiol 61:555-588, 2007, http://dx.doi.org/10.1146/annurev.micro.61.080706.093224). That review began a process of considering outer spore layers as an integrated, multilayered structure rather than simply regarding the outer spore components as independent parts.
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Next-Generation Bacillus anthracis Live Attenuated Spore Vaccine Based on the htrA(-) (High Temperature Requirement A) Sterne Strain. Sci Rep 2016; 6:18908. [PMID: 26732659 PMCID: PMC4702213 DOI: 10.1038/srep18908] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 11/30/2015] [Indexed: 12/17/2022] Open
Abstract
Anthrax is a lethal disease caused by the gram-positive spore-producing bacterium Bacillus anthracis. Live attenuated vaccines, such as the nonencapsulated Sterne strain, do not meet the safety standards mandated for human use in the Western world and are approved for veterinary purposes only. Here we demonstrate that disrupting the htrA gene, encoding the chaperone/protease HtrA (High Temperature Requirement A), in the virulent Bacillus anthracis Vollum strain results in significant virulence attenuation in guinea pigs, rabbits and mice, underlying the universality of the attenuated phenotype associated with htrA knockout. Accordingly, htrA disruption was implemented for the development of a Sterne-derived safe live vaccine compatible with human use. The novel B. anthracis SterneΔhtrA strain secretes functional anthrax toxins but is 10–104-fold less virulent than the Sterne vaccine strain depending on animal model (mice, guinea pigs, or rabbits). In spite of this attenuation, double or even single immunization with SterneΔhtrA spores elicits immune responses which target toxaemia and bacteremia resulting in protection from subcutaneous or respiratory lethal challenge with a virulent strain in guinea pigs and rabbits. The efficacy of the immune-protective response in guinea pigs was maintained for at least 50 weeks after a single immunization.
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Kaur M, Singh S, Bhatnagar R. Anthrax vaccines: present status and future prospects. Expert Rev Vaccines 2014; 12:955-70. [PMID: 23984963 DOI: 10.1586/14760584.2013.814860] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The management of anthrax remains a top priority among the biowarfare/bioterror agents. It was the Bacillus anthracis spore attack through the US mail system after the September 11, 2001, terrorist attacks in the USA that highlighted the potential of B. anthracis as a bioterrorism agent and the threat posed by its deliberate dissemination. These attacks invigorated the efforts toward understanding the anthrax pathogenesis and development of more comprehensive medical intervention strategies for its containment in case of both natural disease and manmade, accidental or deliberate infection of a non-suspecting population. Currently, efforts are directed toward the development of safe and efficacious vaccines as well as intervention tools for controlling the disease in the advanced fulminant stage when toxemia has already developed. This work presents an overview of the current understanding of anthrax pathogenesis and recent advances made, particularly after 2001, for the successful management of anthrax and outlines future perspectives.
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Affiliation(s)
- Manpreet Kaur
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, Delhi, India
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15
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Whole-Genome Sequencing of the Nonproteolytic Bacillus anthracis V770-NP1-R Strain Reveals Multiple Mutations in Peptidase Loci. GENOME ANNOUNCEMENTS 2014; 2:2/1/e00075-14. [PMID: 24526646 PMCID: PMC3924378 DOI: 10.1128/genomea.00075-14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
We report the draft whole-genome sequence of the nonproteolytic Bacillus anthracis V770-NP1-R strain. Compared to those of other B. anthracis strains, the genome exhibits unique mutations in multiple targets potentially affecting proteolytic functions. One of these mutations is a deletion that disrupts the NprR quorum-sensing regulator of the NprA protease.
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Cohen N, Mechaly A, Mazor O, Fisher M, Zahavy E. Rapid Homogenous Time-Resolved Fluorescence (HTRF) Immunoassay for Anthrax Detection. J Fluoresc 2014; 24:795-801. [DOI: 10.1007/s10895-014-1354-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 01/27/2014] [Indexed: 10/25/2022]
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Makam SS, Kingston JJ, Harischandra MS, Batra HV. Protective antigen and extractable antigen 1 based chimeric protein confers protection against Bacillus anthracis in mouse model. Mol Immunol 2014; 59:91-9. [PMID: 24513572 DOI: 10.1016/j.molimm.2014.01.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 01/09/2014] [Accepted: 01/13/2014] [Indexed: 10/25/2022]
Abstract
Recombinant bivalent chimeric protein was generated comprising of domain 4 of protective antigen (PA4) and carboxy terminal region of extractable antigen 1 (EA1C) by overlap extension PCR. The immunogenicity and protective efficacy of recombinant chimeric protein (PE) and protein mixture (PAEA) along with the individual components, PA4 and EA1C were evaluated in this study. We found that PE and PAEA exhibited higher endpoint titer and elevated IgG1 response. Compared to PA4 and EA1C, the chimeric protein PE and protein mixture PAEA exhibited 1.52 and 1.39 times more proliferative effect on lymphocytes in vitro. The spore uptake by anti-PE and anti-PAEA antibodies was significantly more than the individual components. We further evaluated the effects of antisera on the toxins in vitro and in vivo. Anti-PE and anti-PAEA antibodies displayed nearly 80% protection against crude toxin activity on RAW 264.7 cell lines. We further demonstrated that the anti-PE and anti-PAEA antibodies displayed better protection in controlling the edema induced by crude toxin. Passive immunization with anti-PE and anti-PAEA provided protection against toxin challenge in mice. The present study reveals that the chimeric protein consisting of heterologous regions of PA and EA1 can render better protection than PA4 or EA1C alone against toxins and bacilli.
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Affiliation(s)
- Shivakiran S Makam
- Microbiology Division, Defence Food Research Laboratory, Siddarthanagar, Mysore 570011, Karnataka, India
| | - Joseph J Kingston
- Microbiology Division, Defence Food Research Laboratory, Siddarthanagar, Mysore 570011, Karnataka, India
| | - Murali S Harischandra
- Microbiology Division, Defence Food Research Laboratory, Siddarthanagar, Mysore 570011, Karnataka, India
| | - Harsh V Batra
- Microbiology Division, Defence Food Research Laboratory, Siddarthanagar, Mysore 570011, Karnataka, India.
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Levy H, Glinert I, Weiss S, Sittner A, Schlomovitz J, Altboum Z, Kobiler D. Toxin-independent virulence of Bacillus anthracis in rabbits. PLoS One 2014; 9:e84947. [PMID: 24416317 PMCID: PMC3885664 DOI: 10.1371/journal.pone.0084947] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 11/14/2013] [Indexed: 12/24/2022] Open
Abstract
The accepted paradigm states that anthrax is both an invasive and toxinogenic disease and that the toxins play a major role in pathogenicity. In the guinea pig (GP) model we have previously shown that deletion of all three toxin components results in a relatively moderate attenuation in virulence, indicating that B. anthracis possesses an additional toxin-independent virulence mechanism. To characterize this toxin-independent mechanism in anthrax disease, we developed a new rabbit model by intravenous injection (IV) of B. anthracis encapsulated vegetative cells, artificially creating bacteremia. Using this model we were able to demonstrate that also in rabbits, B. anthracis mutants lacking the toxins are capable of killing the host within 24 hours. This virulent trait depends on the activity of AtxA in the presence of pXO2, as, in the absence of the toxin genes, deletion of either component abolishes virulence. Furthermore, this IV virulence depends mainly on AtxA rather than the whole pXO1. A similar pattern was shown in the GP model using subcutaneous (SC) administration of spores of the mutant strains, demonstrating the generality of the phenomenon. The virulent strains showed higher bacteremia levels and more efficient tissue dissemination; however our interpretation is that tissue dissemination per se is not the main determinant of virulence whose exact nature requires further elucidation.
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Affiliation(s)
- Haim Levy
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
- * E-mail:
| | - Itai Glinert
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Shay Weiss
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Assa Sittner
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Josef Schlomovitz
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Zeev Altboum
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
| | - David Kobiler
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness Ziona, Israel
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Chun JH, Choi OJ, Cho MH, Hong KJ, Seong WK, Oh HB, Rhie GE. Serological Correlate of Protection in Guinea Pigs for a Recombinant Protective Antigen Anthrax Vaccine Produced from Bacillus brevis. Osong Public Health Res Perspect 2013; 3:170-6. [PMID: 24159510 PMCID: PMC3738701 DOI: 10.1016/j.phrp.2012.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2012] [Revised: 07/18/2012] [Accepted: 07/19/2012] [Indexed: 11/30/2022] Open
Abstract
Objective Recombinant protective antigen (rPA) is the active pharmaceutical ingredient of a second generation anthrax vaccine undergoing clinical trials both in Korea and the USA. By using the rPA produced from Bacillus brevis pNU212 expression system, correlations of serological immune response to anthrax protection efficacy were analyzed in a guinea pig model. Methods Serological responses of rPA anthrax vaccine were investigated in guinea pigs that were given single or two injections (interval of 4 weeks) of various amounts of rPA combined with aluminumhydroxide adjuvant. Guinea pigs were subsequently challenged by the intramuscular injection with 30 half-lethal doses (30LD50) of virulent Bacillus anthracis spores. Serumantibody titerswere determined by anti-PA IgGELISA and the ability of antibodies to neutralize the cytotoxicity of lethal toxin on J774A.1 cell was measured through the toxin neutralizing antibody (TNA) assay. Results To examine correlations between survival rate and antibody titers, correlation between neutralizing antibody titers and the extent of protection was determined. Toxin neutralization titers of at least 1176 were sufficient to confer protection against a dose of 30LD50 of virulent anthrax spores of the H9401 strain. Such consistency in the correlation was not observed from those antibody titers determined by ELISA. Conclusion Neutralizing-antibody titers can be used as a surrogate marker.
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20
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Liu X, Wang D, Ren J, Tong C, Feng E, Wang X, Zhu L, Wang H. Identification of the immunogenic spore and vegetative proteins of Bacillus anthracis vaccine strain A16R. PLoS One 2013; 8:e57959. [PMID: 23516421 PMCID: PMC3596338 DOI: 10.1371/journal.pone.0057959] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 01/29/2013] [Indexed: 01/03/2023] Open
Abstract
Immunoproteomics was used to screen the immunogenic spore and vegetative proteins of Bacillus anthracis vaccine strain A16R. The spore and vegetative proteins were separated by 2D gel electrophoresis and transferred to polyvinylidene difluoride membranes, and then western blotting was performed with rabbit immune serum against B.anthracis live spores. Immunogenic spots were cut and digested by trypsin. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry was performed to identify the proteins. As a result, 11 and 45 immunogenic proteins were identified in the spores and vegetative cells, respectively; 26 of which have not been reported previously. To verify their immunogenicity, 12 of the identified proteins were selected to be expressed, and the immune sera from the mice vaccinated by the 12 expressed proteins, except BA0887, had a specific western blot band with the A16R whole cellular lytic proteins. Some of these immunogenic proteins might be used as novel vaccine candidates themselves or for enhancing the protective efficacy of a protective-antigen-based vaccine.
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Affiliation(s)
- Xiankai Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing, People's Republic of China
| | - Dongshu Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing, People's Republic of China
| | - Jingxiao Ren
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing, People's Republic of China
| | - Chao Tong
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing, People's Republic of China
| | - Erling Feng
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing, People's Republic of China
| | - Xuefang Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing, People's Republic of China
| | - Li Zhu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing, People's Republic of China
- * E-mail: (LZ); (HW)
| | - Hengliang Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing, People's Republic of China
- * E-mail: (LZ); (HW)
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A novel homogeneous immunoassay for anthrax detection based on the AlphaLISA method: detection of B. anthracis spores and protective antigen (PA) in complex samples. Anal Bioanal Chem 2013; 405:3965-72. [DOI: 10.1007/s00216-013-6752-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 12/17/2012] [Accepted: 01/16/2013] [Indexed: 02/07/2023]
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22
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Friedlander AM, Grabenstein JD, Brachman PS. Anthrax vaccines. Vaccines (Basel) 2013. [DOI: 10.1016/b978-1-4557-0090-5.00022-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Sinha K, Bhatnagar R. Recombinant GroEL enhances protective antigen-mediated protection against Bacillus anthracis spore challenge. Med Microbiol Immunol 2012; 202:153-65. [PMID: 23263010 DOI: 10.1007/s00430-012-0280-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2012] [Accepted: 11/27/2012] [Indexed: 11/27/2022]
Abstract
The fatal inhalation infection caused by Bacillus anthracis results from a complex pathogenic cycle involving release of toxins by bacteria that germinate from spores. Currently available vaccines against anthrax consist of protective antigen (PA), one of the anthrax toxin components. However, these PA-based vaccines are only partially protective against spore challenge in mice. This shows that exclusive elicitation of high anti-PA titer does not directly correlate with protection. Here, we demonstrate that inclusion of GroEL of B. anthracis with PA elicits enhanced protection against anthrax spore challenge in mice. GroEL was included as it has been reported to be present both on the exosporium and in the secretome in addition to the cell surface of B. anthracis. It has also been found protective against other pathogens. In the present study, immunization with GroEL alone was also potent enough to induce high humoral and cell-mediated response and significantly prolonged the mean time to death in spore-challenged mice. As a surface antigen, opsonization of spores with anti-GroEL IgG showed increased uptake of treated spores and therefore accelerated rate of spore destruction by phagocytic cells leading to the protection of mice. We found that GroEL was able to enhance nitric oxide release from lymphocytes and also reduce bacterial load from the organs, probably through the activation of macrophages and over-expression of certain innate immunity receptors. Therefore, the present study emphasizes that GroEL is an effective immunomodulator against B. anthracis infection.
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Affiliation(s)
- Kanchan Sinha
- Molecular Biology and Genetic Engineering Laboratory, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India.
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Immunization of mice with formalin-inactivated spores from avirulent Bacillus cereus strains provides significant protection from challenge with Bacillus anthracis Ames. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2012; 20:56-65. [PMID: 23114705 DOI: 10.1128/cvi.00550-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Bacillus anthracis spores are the infectious form of the organism for humans and animals. However, the approved human vaccine in the United States is derived from a vegetative culture filtrate of a toxigenic, nonencapsulated B. anthracis strain that primarily contains protective antigen (PA). Immunization of mice with purified spore proteins and formalin-inactivated spores (FIS) from a nonencapsulated, nontoxigenic B. anthracis strain confers protection against B. anthracis challenge when PA is also administered. To investigate the capacity of the spore particle to act as a vaccine without PA, we immunized mice subcutaneously with FIS from nontoxigenic, nonencapsulated B. cereus strain G9241 pBCXO1(-)/pBC210(-) (dcG9241), dcG9241 ΔbclA, or 569-UM20 or with exosporium isolated from dcG9241. FIS vaccination provided significant protection of mice from intraperitoneal or intranasal challenge with spores of the virulent B. anthracis Ames or Ames ΔbclA strain. Immunization with dcG9241 ΔbclA FIS, which are devoid of the immunodominant spore protein BclA, provided greater protection from challenge with either Ames strain than did immunization with FIS from BclA-producing strains. In addition, we used prechallenge immune antisera to probe a panel of recombinant B. anthracis Sterne spore proteins to identify novel immunogenic vaccine candidates. The antisera were variably reactive with BclA and with 10 other proteins, four of which were previously tested as vaccine candidates. Overall our data show that immunization with FIS from nontoxigenic, nonencapsulated B. cereus strains provides moderate to high levels of protection of mice from B. anthracis Ames challenge and that neither PA nor BclA is required for this protection.
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Differential contribution of Bacillus anthracis toxins to pathogenicity in two animal models. Infect Immun 2012; 80:2623-31. [PMID: 22585968 DOI: 10.1128/iai.00244-12] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The virulence of Bacillus anthracis, the causative agent of anthrax, stems from its antiphagocytic capsule, encoded by pXO2, and the tripartite toxins encoded by pXO1. The accepted paradigm states that anthrax is both an invasive and toxinogenic disease and that the toxins play major roles in pathogenicity. We tested this assumption by a systematic study of mutants with combined deletions of the pag, lef, and cya genes, encoding protective antigen (PA), lethal factor (LF), and edema factor (EF), respectively. The resulting seven mutants (single, double, and triple) were evaluated following subcutaneous (s.c.) and intranasal (i.n.) inoculation in rabbits and guinea pigs. In the rabbit model, virulence is completely dependent on the presence of PA. Any mutant bearing a pag deletion behaved like a pXO1-cured mutant, exhibiting complete loss of virulence with attenuation indices of over 2,500,000 or 1,250 in the s.c. or i.n. route of infection, respectively. In marked contrast, in guinea pigs, deletion of pag or even of all three toxin components resulted in relatively moderate attenuation, whereas the pXO1-cured bacteria showed complete attenuation. The results indicate that a pXO1-encoded factor(s), other than the toxins, has a major contribution to the virulence mechanism of B. anthracis in the guinea pig model. These unexpected toxin-dependent and toxin-independent manifestations of pathogenicity in different animal models emphasize the importance and need for a comprehensive evaluation of B. anthracis virulence in general and in particular for the design of relevant next-generation anthrax vaccines.
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Uchida M, Harada T, Enkhtuya J, Kusumoto A, Kobayashi Y, Chiba S, Shyaka A, Kawamoto K. Protective effect of Bacillus anthracis surface protein EA1 against anthrax in mice. Biochem Biophys Res Commun 2012; 421:323-8. [DOI: 10.1016/j.bbrc.2012.04.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 04/02/2012] [Indexed: 12/31/2022]
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Rapid detection methods for Bacillus anthracis in environmental samples: a review. Appl Microbiol Biotechnol 2012; 93:1411-22. [DOI: 10.1007/s00253-011-3845-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 12/12/2011] [Accepted: 12/14/2011] [Indexed: 12/11/2022]
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Mikshis NI, Kudryavtseva OM, Shulepov DV, Goncharova AY, Bolotnikova MF, Novikova LV, Popov YA, Kutyrev VV. Asporogenic recombinant producer of anthrax protective antigen. APPL BIOCHEM MICRO+ 2011. [DOI: 10.1134/s0003683811070088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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The effect of deletion of the edema factor on Bacillus anthracis pathogenicity in guinea pigs and rabbits. Microb Pathog 2011; 52:55-60. [PMID: 22020310 DOI: 10.1016/j.micpath.2011.10.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 10/06/2011] [Accepted: 10/10/2011] [Indexed: 11/21/2022]
Abstract
Bacillus anthracis secretes three major components, which assemble into two bipartite toxins: lethal toxin (LT), composed of lethal factor (LF) and protective antigen (PA) and edema toxin (ET), composed of edema factor (EF) and PA. EF is a potent calmodulin-dependent adenylate cyclase, which is internalized into the target cell following PA binding. Once inside the cell, EF elevates cAMP levels, interrupting intracellular signaling. Effects of ET were demonstrated on monocytes, neutrophils and T-cells. In an earlier work we demonstrated that a deletion of LF in a fully virulent strain had no effect in guinea pigs and a significant, but not major, effect in the rabbit model. These results suggested that EF might play an important role in the development of infection and mortality following exposure to B. anthracis spores. To evaluate the role of EF in B. anthracis pathogenicity we deleted the cya gene, which encodes the EF protein, in the fully virulent Vollum strain. The Δcya mutant was fully virulent in the guinea pig model as determined by LD(50) experiments. In the rabbit model, when infected subcutaneously, the absence of EF had no effect on the virulence of the mutant. However an increase of two orders of magnitude in the LD(50) was demonstrated when the rabbits were infected by intranasal instillation accompanied with partial mortality and increased mean time to death. These results argue that in the guinea pig model the presence of one of the toxins, ET or LT is sufficient for the development of the infection. In the rabbit model ET plays a role in respiratory infection, most probably mediating the early steps of host colonization.
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Chitlaru T, Zaide G, Ehrlich S, Inbar I, Cohen O, Shafferman A. HtrA is a major virulence determinant of Bacillus anthracis. Mol Microbiol 2011; 81:1542-59. [PMID: 21801240 DOI: 10.1111/j.1365-2958.2011.07790.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We demonstrate that disruption of the htrA (high temperature requirement A) gene in either the virulent Bacillus anthracis Vollum (pXO1(+) , pXO2(+) ), or in the ΔVollum (pXO1(-), pXO2(-), nontoxinogenic and noncapsular) strains, affect significantly the ability of the resulting mutants to withstand heat, oxidative, ethanol and osmotic stress. The ΔhtrA mutants manifest altered secretion of several proteins, as well as complete silencing of the abundant extracellular starvation-associated neutral protease A (NprA). VollumΔhtrA bacteria exhibit delayed proliferation in a macrophage infection assay, and despite their ability to synthesize the major B. anthracis toxins LT (lethal toxin) and ET (oedema toxin) as well as the capsule, show a decrease of over six orders of magnitude in virulence (lethal dose 50% = 3 × 10(8) spores, in the guinea pig model of anthrax), as compared with the parental wild-type strain. This unprecedented extent of loss of virulence in B. anthracis, as a consequence of deletion of a single gene, as well as all other phenotypic defects associated with htrA mutation, are restored in their corresponding trans-complemented strains. It is suggested that the loss of virulence is due to increased susceptibility of the ΔhtrA bacteria to stress insults encountered in the host. On a practical note, it is demonstrated that the attenuated Vollum ΔhtrA is highly efficacious in protecting guinea pigs against a lethal anthrax challenge.
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Affiliation(s)
- Theodor Chitlaru
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona 74100, Israel
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Levy H, Weiss S, Altboum Z, Schlomovitz J, Rothschild N, Blachinsky E, Kobiler D. Lethal factor is not required for Bacillus anthracis virulence in guinea pigs and rabbits. Microb Pathog 2011; 51:345-51. [PMID: 21791242 DOI: 10.1016/j.micpath.2011.07.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 06/26/2011] [Accepted: 07/06/2011] [Indexed: 11/26/2022]
Abstract
The major virulence factor of Bacillus anthracis is the tripartite anthrax toxin, comprising the protective antigen (PA), lethal factor (LF) and edema factor (EF). The LF of B. anthracis is a metalloprotease that has been shown to play an important role in pathogenicity. Deletion of this gene (lef) in the Sterne strain was reported to dramatically reduce the pathogenicity of this strain in mice, and was reported to be as dramatic as the deletion of PA. We evaluated the effect on pathogenicity of the lef deletion in the fully virulent Vollum strain in guinea pigs and NZW rabbits by either subcutaneous injection or intranasal instillation. In guinea pigs, no major differences between the mutant strain and the wild type could be detected in the LD(50) or mean time to death values. On the other hand, the lef deletion caused death of 50-70% of all rabbits infected with the mutant spores at doses equivalent or higher than the wild type LD(50). The surviving rabbits, which were infected with spore doses higher than the wild type LD(50), developed a protective immune response that conferred resistance to challenge with the wild type strain. These findings may indicate that the mutant lacking the LF is capable of host colonization which causes death in 50-70% of the animals and a protective immune response in the others. These results indicate that unlike the data obtained in mice, the LF mutation does not abolish B. anthracis pathogenicity.
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Affiliation(s)
- Haim Levy
- Department of Infectious Diseases, Israel Institute for Biological Research, 74100 Ness Ziona, Israel.
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Chitlaru T, Altboum Z, Reuveny S, Shafferman A. Progress and novel strategies in vaccine development and treatment of anthrax. Immunol Rev 2011; 239:221-36. [PMID: 21198675 DOI: 10.1111/j.1600-065x.2010.00969.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The lethal anthrax disease is caused by spores of the gram-positive Bacillus anthracis, a member of the cereus group of bacilli. Although the disease is very rare in the Western world, development of anthrax countermeasures gains increasing attention due to the potential use of B. anthracis spores as a bio-terror weapon. Protective antigen (PA), the non-toxic subunit of the bacterial secreted exotoxin, fulfills the role of recognizing a specific receptor and mediating the entry of the toxin into the host target cells. PA elicits a protective immune response and represents the basis for all current anthrax vaccines. Anti-PA neutralizing antibodies are useful correlates for protection and for vaccine efficacy evaluation. Post exposure anti-toxemic and anti-bacteremic prophylactic treatment of anthrax requires prolonged antibiotic administration. Shorter efficient postexposure treatments may require active or passive immunization, in addition to antibiotics. Although anthrax is acknowledged as a toxinogenic disease, additional factors, other than the bacterial toxin, may be involved in the virulence of B. anthracis and may be needed for the long-lasting protection conferred by PA immunization. The search for such novel factors is the focus of several high throughput genomic and proteomic studies that are already leading to identification of novel targets for therapeutics, for vaccine candidates, as well as biomarkers for detection and diagnosis.
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Affiliation(s)
- Theodor Chitlaru
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
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Identification of an African Bacillus anthracis lineage that lacks expression of the spore surface-associated anthrose-containing oligosaccharide. J Bacteriol 2011; 193:3506-11. [PMID: 21571994 DOI: 10.1128/jb.00078-11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The surfaces of Bacillus anthracis endospores expose a pentasaccharide containing the monosaccharide anthrose, which has been considered for use as a vaccine or target for specific detection of the spores. In this study B. anthracis strains isolated from cattle carcasses in African countries where anthrax is endemic were tested for their cross-reactivity with monoclonal antibodies (MAbs) specific for anthrose-containing oligosaccharides. Unexpectedly, none of the isolates collected in Chad, Cameroon, and Mali were recognized by the MAbs. Sequencing of the four-gene operon encoding anthrose biosynthetic enzymes revealed the presence of premature stop codons in the aminotransferase and glycosyltransferase genes in all isolates from Chad, Cameroon, and Mali. Both immunological and genetic findings suggest that the West African isolates are unable to produce anthrose. The anthrose-deficient strains from West Africa belong to a particular genetic lineage. Immunization of cattle in Chad with a locally produced vaccine based on anthrose-positive spores of the B. anthracis strain Sterne elicited an anti-carbohydrate IgG response specific for a synthetic anthrose-containing tetrasaccharide as demonstrated by glycan microarray analysis. Competition immunoblots with synthetic pentasaccharide derivatives suggested an immunodominant role of the anthrose-containing carbohydrate in cattle. In West Africa anthrax is highly endemic. Massive vaccination of livestock in this area has taken place over long periods of time using spores of the anthrose-positive vaccine strain Sterne. The spread of anthrose-deficient strains in this region may represent an escape strategy of B. anthracis.
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Thomas J, Epshtein Y, Chopra A, Ordog B, Ghassemi M, Christman JW, Nattel S, Cook JL, Levitan I. Anthrax lethal factor activates K(+) channels to induce IL-1β secretion in macrophages. THE JOURNAL OF IMMUNOLOGY 2011; 186:5236-43. [PMID: 21421849 DOI: 10.4049/jimmunol.1001078] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Anthrax lethal toxin (LeTx) is a virulence factor of Bacilillus anthracis that is a bivalent toxin, containing lethal factor (LF) and protective Ag proteins, which causes cytotoxicity and altered macrophage function. LeTx exposure results in early K(+) efflux from macrophages associated with caspase-1 activation and increased IL-1β release. The mechanism of this toxin-induced K(+) efflux is unknown. The goals of the current study were to determine whether LeTx-induced K(+) efflux from macrophages is mediated by toxin effects on specific K(+) channels and whether altered K(+)-channel activity is involved in LeTx-induced IL-1β release. Exposure of macrophages to LeTx induced a significant increase in the activities of two types of K(+) channels that have been identified in mouse macrophages: Ba(2+)-sensitive inwardly rectifying K(+) (Kir) channels and 4-aminopyridine-sensitive outwardly rectifying voltage-gated K(+) (Kv) channels. LeTx enhancement of both Kir and Kv required the proteolytic activity of LF, because exposure of macrophages to a mutant LF-protein (LF(E687C)) combined with protective Ag protein had no effect on the currents. Furthermore, blocking Kir and Kv channels significantly decreased LeTx-induced release of IL-1β. In addition, retroviral transduction of macrophages with wild-type Kir enhanced LeTx-induced release of IL-1β, whereas transduction of dominant-negative Kir blocked LeTx-induced release of IL-1β. Activation of caspase-1 was not required for LeTx-induced activation of either of the K(+) channels. These data indicate that a major mechanism through which LeTx stimulates macrophages to release IL-1β involves an LF-protease effect that enhances Kir and Kv channel function during toxin stimulation.
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Affiliation(s)
- Johnson Thomas
- Section of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA
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Identification and characterization of novel and potent transcription promoters of Francisella tularensis. Appl Environ Microbiol 2010; 77:1608-18. [PMID: 21193666 DOI: 10.1128/aem.01862-10] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two alternative promoter trap libraries, based on the green fluorescence protein (gfp) reporter and on the chloramphenicol acetyltransferase (cat) cassette, were constructed for isolation of potent Francisella tularensis promoters. Of the 26,000 F. tularensis strain LVS gfp library clones, only 3 exhibited visible fluorescence following UV illumination and all appeared to carry the bacterioferritin promoter (Pbfr). Out of a total of 2,000 chloramphenicol-resistant LVS clones isolated from the cat promoter library, we arbitrarily selected 40 for further analysis. Over 80% of these clones carry unique F. tularensis DNA sequences which appear to drive a wide range of protein expression, as determined by specific chloramphenicol acetyltransferase (CAT) Western dot blot and enzymatic assays. The DNA sequence information for the 33 unique and novel F. tularensis promoters reported here, along with the results of in silico and primer extension analyses, suggest that F. tularensis possesses classical Escherichia coli σ(70)-related promoter motifs. These motifs include the -10 (TATAAT) and -35 [TTGA(C/T)A] domains and an AT-rich region upstream from -35, reminiscent of but distinct from the E. coli upstream region that is termed the UP element. The most efficient promoter identified (Pbfr) appears to be about 10 times more potent than the F. tularensis groEL promoter and is probably among the strongest promoters in F. tularensis. The battery of promoters identified in this work will be useful, among other things, for genetic manipulation in the background of F. tularensis intended to gain better understanding of the mechanisms involved in pathogenesis and virulence, as well as for vaccine development studies.
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Sinha K, Bhatnagar R. GroEL provides protection against Bacillus anthracis infection in BALB/c mice. Mol Immunol 2010; 48:264-71. [PMID: 20832865 DOI: 10.1016/j.molimm.2010.08.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2010] [Revised: 08/06/2010] [Accepted: 08/07/2010] [Indexed: 01/22/2023]
Abstract
Heat shock proteins (Hsps) of the HSP60 and HSP70 family are highly conserved and essential to all living organisms. Hsps are immunodominant in numerous microbial infections and have been investigated for their vaccine potential. We investigated the immunogenicity and protective efficacy of GroEL and DnaK of B. anthracis in murine model. Both Hsps were found to be highly immunogenic with mixed antibody response (both IgG1 and IgG2a), indicating stimulation of both humoral and cell-mediated immunity. Cytokine profile also confirmed robust T-cell response with increase in lymphocyte proliferation. Immunization with GroEL conferred 100% protection to mice against B. anthracis infection whereas DnaK couldn't provide protection.
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Affiliation(s)
- Kanchan Sinha
- School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India.
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Klinman DM, Yamamoto M, Tross D, Tomaru K. Anthrax prevention and treatment: utility of therapy combining antibiotic plus vaccine. Expert Opin Biol Ther 2010; 9:1477-86. [PMID: 19769541 DOI: 10.1517/14712590903307347] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The intentional release of anthrax spores in 2001 confirmed this pathogen's ability to cause widespread panic, morbidity and mortality. While individuals exposed to anthrax can be successfully treated with antibiotics, pre-exposure vaccination can reduce susceptibility to infection-induced illness. Concern over the safety and immunogenicity of the licensed US vaccine (Anthrax Vaccine Adsorbed (AVA)) has fueled research into alternatives. Second-generation anthrax vaccines based on purified recombinant protective antigen (rPA) have entered clinical trials. These rPA vaccines induce neutralizing antibodies that prevent illness, but the magnitude and duration of the resultant protective response is modest. Efforts are underway to bolster the immunogenicity of rPA by combining it with adjuvants and other immunostimulatory agents. Third generation vaccines are under development that utilize a wide variety of immunization platforms, antigens, adjuvants, delivery methods and routes of delivery to optimize the induction of a protective immunity. For the foreseeable future, vaccination will rely on first and second generation vaccines co-administered with immune adjuvants. Optimal post-exposure treatment of immunologically naive individuals should include a combination of vaccine plus antibiotic therapy.
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Affiliation(s)
- Dennis M Klinman
- National Cancer Institute (NCI), NCI, NIH, Frederick, MD 21702, USA.
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Zahavy E, Heleg-Shabtai V, Zafrani Y, Marciano D, Yitzhaki S. Application of Fluorescent Nanocrystals (q-dots) for the Detection of Pathogenic Bacteria by Flow-Cytometry. J Fluoresc 2009; 20:389-99. [DOI: 10.1007/s10895-009-0546-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Accepted: 09/15/2009] [Indexed: 10/20/2022]
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Abstract
Bacillus anthracis is a Gram-positive, spore-forming bacterium representing the etiological cause of anthrax, a rare lethal disease of animals and humans. Development of anthrax countermeasures has gained increasing attention owing to the potential use of B. anthracis spores as a bioterror weapon. The various forms of infection by B. anthracis are characterized both by toxemia and septicemia, both of which are the result of spore entry into the host followed by their germination into rapidly multiplying, toxin-producing bacilli. Following the publication of the bacterial genome, proteomic studies were carried out to determine the protein composition of the spore and identify exposed vegetative (membrane-located or secreted) proteins. These studies included comparison of strains differing in their virulence, cultured under different conditions and, in some cases, were complemented by serological inspection, which addressed expression during infection of proteomically identified proteins and their immunogenicity. The proteomic approach emerged as a valuable strategy for the generation of a pool of potential B. anthracis protein targets for further evaluation in detection, diagnostics, therapy and prophylaxis, and contributed to the elucidation of some aspects of the pathogenesis of the disease.
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Affiliation(s)
- Theodor Chitlaru
- Department of Biochemistry & Molecular Genetics, Israel Institute for Biological Research, PO Box 19, Ness-Ziona 74100, Israel
| | - Avigdor Shafferman
- Department of Biochemistry & Molecular Genetics, Israel Institute for Biological Research, PO Box 19, Ness-Ziona 74100, Israel
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Sela-Abramovich S, Chitlaru T, Gat O, Grosfeld H, Cohen O, Shafferman A. Novel and unique diagnostic biomarkers for Bacillus anthracis infection. Appl Environ Microbiol 2009; 75:6157-67. [PMID: 19648366 PMCID: PMC2753070 DOI: 10.1128/aem.00766-09] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2009] [Accepted: 07/22/2009] [Indexed: 01/28/2023] Open
Abstract
A search for bacterium-specific biomarkers in peripheral blood following infection with Bacillus anthracis was carried out with rabbits, using a battery of specific antibodies generated by DNA vaccination against 10 preselected highly immunogenic bacterial antigens which were identified previously by a genomic/proteomic/serologic screen of the B. anthracis secretome. Detection of infection biomarkers in the circulation of infected rabbits could be achieved only after removal of highly abundant serum proteins by chromatography using a random-ligand affinity column. Besides the toxin component protective antigen, the following three secreted proteins were detected in the circulation of infected animals: the chaperone and protease HtrA (BA3660), an NlpC/P60 endopeptidase (BA1952), and a protein of unknown function harboring two SH3 (Src homology 3) domains (BA0796). The three proteins could be detected in plasma samples from infected animals exhibiting 10(3) to 10(5) CFU/ml blood and also in standard blood cultures at 3 to 6 h post-bacterial inoculation at a bacteremic level as low as 10(3) CFU/ml. Furthermore, the three biomarkers appear to be present only in the secretome of B. anthracis, not in those of the related pathogens B. thuringiensis and B. cereus. To the best of our knowledge, this is the first report of direct detection of B. anthracis-specific proteins, other than the toxin components, in the circulation of infected animals.
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Affiliation(s)
- Sagit Sela-Abramovich
- Department of Biochemistry and Molecular Genetics, Life Science Research Israel Ltd, 2 Ness-Ziona 74100, Israel
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Cybulski RJ, Sanz P, O'Brien AD. Anthrax vaccination strategies. Mol Aspects Med 2009; 30:490-502. [PMID: 19729034 DOI: 10.1016/j.mam.2009.08.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Accepted: 08/24/2009] [Indexed: 01/10/2023]
Abstract
The biological attack conducted through the US postal system in 2001 broadened the threat posed by anthrax from one pertinent mainly to soldiers on the battlefield to one understood to exist throughout our society. The expansion of the threatened population placed greater emphasis on the reexamination of how we vaccinate against Bacillus anthracis. The currently-licensed Anthrax Vaccine, Adsorbed (AVA) and Anthrax Vaccine, Precipitated (AVP) are capable of generating a protective immune response but are hampered by shortcomings that make their widespread use undesirable or infeasible. Efforts to gain US Food and Drug Administration (FDA) approval for licensure of a second generation recombinant protective antigen (rPA)-based anthrax vaccine are ongoing. However, this vaccine's reliance on the generation of a humoral immune response against a single virulence factor has led a number of scientists to conclude that the vaccine is likely not the final solution to optimal anthrax vaccine design. Other vaccine approaches, which seek a more comprehensive immune response targeted at multiple components of the B. anthracis organism, are under active investigation. This review seeks to summarize work that has been done to build on the current PA-based vaccine methodology and to evaluate the search for future anthrax prophylaxis strategies.
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Affiliation(s)
- Robert J Cybulski
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, United States
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Rosenfeld R, Marcus H, Ben-Arie E, Lachmi BE, Mechaly A, Reuveny S, Gat O, Mazor O, Ordentlich A. Isolation and chimerization of a highly neutralizing antibody conferring passive protection against lethal Bacillus anthracis infection. PLoS One 2009; 4:e6351. [PMID: 19629185 PMCID: PMC2710523 DOI: 10.1371/journal.pone.0006351] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2009] [Accepted: 06/22/2009] [Indexed: 11/18/2022] Open
Abstract
Several studies have demonstrated that the passive transfer of protective antigen (PA)-neutralizing antibodies can protect animals against Bacillus anthracis infection. The standard protocol for the isolation of PA-neutralizing monoclonal antibodies is based upon a primary selection of the highest PA-binders by ELISA, and usually yields only few candidates antibodies. We demonstrated that by applying a PA-neutralization functionality-based screen as the primary criterion for positive clones, it was possible to isolate more than 100 PA-neutralizing antibodies, some of which exhibited no measurable anti-PA titers in ELISA. Among the large panel of neutralizing antibodies identified, mAb 29 demonstrated the most potent activity, and was therefore chimerized. The variable region genes of the mAb 29 were fused to human constant region genes, to form the chimeric 29 antibody (cAb 29). Guinea pigs were fully protected against infection by 40LD(50)B. anthracis spores following two separate administrations with 10 mg/kg of cAb 29: the first administration was given before the challenge, and a second dose was administered on day 4 following exposure. Moreover, animals that survived the challenge and developed endogenous PA-neutralizing antibodies with neutralizing titers above 100 were fully protected against repeat challenges with 40LD(50) of B. anthracis spores. The data presented here emphasize the importance of toxin neutralization-based screens for the efficient isolation of protective antibodies that were probably overlooked in the standard screening protocol. The protective activity of the chimeric cAb 29 demonstrated in this study suggest that it may serve as an effective immunotherapeutic agent against anthrax.
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Affiliation(s)
- Ronit Rosenfeld
- Departments of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Hadar Marcus
- Department of Biotechnology, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Einat Ben-Arie
- Departments of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Bat-El Lachmi
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Adva Mechaly
- Department of Infectious Diseases, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Shaul Reuveny
- Department of Biotechnology, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Orit Gat
- Departments of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Ohad Mazor
- Departments of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Arie Ordentlich
- Departments of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona, Israel
- * E-mail:
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Fisher M, Atiya-Nasagi Y, Simon I, Gordin M, Mechaly A, Yitzhaki S. A combined immunomagnetic separation and lateral flow method for a sensitive on-site detection ofBacillus anthracisspores - assessment in water and dairy products. Lett Appl Microbiol 2009; 48:413-8. [DOI: 10.1111/j.1472-765x.2008.02542.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Efficacy of a vaccine based on protective antigen and killed spores against experimental inhalational anthrax. Infect Immun 2008; 77:1197-207. [PMID: 19114543 DOI: 10.1128/iai.01217-08] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Protective antigen (PA)-based anthrax vaccines acting on toxins are less effective than live attenuated vaccines, suggesting that additional antigens may contribute to protective immunity. Several reports indicate that capsule or spore-associated antigens may enhance the protection afforded by PA. Addition of formaldehyde-inactivated spores (FIS) to PA (PA-FIS) elicits total protection against cutaneous anthrax. Nevertheless, vaccines that are effective against cutaneous anthrax may not be so against inhalational anthrax. The aim of this work was to optimize immunization with PA-FIS and to assess vaccine efficacy against inhalational anthrax. We assessed the immune response to recombinant anthrax PA from Bacillus anthracis (rPA)-FIS administered by various immunization protocols and the protection provided to mice and guinea pigs infected through the respiratory route with spores of a virulent strain of B. anthracis. Combined subcutaneous plus intranasal immunization of mice yielded a mucosal immunoglobulin G response to rPA that was more than 20 times higher than that in lung mucosal secretions after subcutaneous vaccination. The titers of toxin-neutralizing antibody and antispore antibody were also significantly higher: nine and eight times higher, respectively. The optimized immunization elicited total protection of mice intranasally infected with the virulent B. anthracis strain 17JB. Guinea pigs were fully protected, both against an intranasal challenge with 100 50% lethal doses (LD(50)) and against an aerosol with 75 LD(50) of spores of the highly virulent strain 9602. Conversely, immunization with PA alone did not elicit protection. These results demonstrate that the association of PA and spores is very much more effective than PA alone against experimental inhalational anthrax.
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Gat O, Zaide G, Inbar I, Grosfeld H, Chitlaru T, Levy H, Shafferman A. Characterization of Bacillus anthracis iron-regulated surface determinant (Isd) proteins containing NEAT domains. Mol Microbiol 2008; 70:983-99. [PMID: 18826411 DOI: 10.1111/j.1365-2958.2008.06460.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Three iron-regulated surface determinant (Isd) proteins, containing NEAr Transporter (NEAT) domains (GBAA4789-7), constitute part of an eight-member Bacillus anthracis operon. GBAA4789 (IsdC), previously characterized by others as a haem-binding protein, and two novel Isd proteins characterized in this study, GBAA4788 (IsdJ) and GBAA4787 (IsdK) proteins, can be translated from two alternative overlapping transcriptional units. The three NEAT-containing Isd proteins are shown to be expressed in vivo during B. anthracis infection. Expression in vitro is regulated by iron ions independent of the virulence plasmids pXO1 and pXO2, yet their presence affects the range of response to iron ion concentration. The expression of IsdC, J and K is strongly repressed under high CO(2) tension, conditions that are optimal for B. anthracis toxin and capsule expression, suggesting that these Isd proteins are elements of a B. anthracis'air-regulon'. Deletion mutants of isdC, isdK or the entire isdCJK locus are as virulent and pathogenic to guinea pigs as the fully virulent wild-type Vollum strain. The isdC-deleted mutant is defective in sequestration of haemin, consistent with previous biochemical observations, while the DeltaisdK mutant is defective in haemoglobin uptake. Studies with recombinant IsdK demonstrate specific binding to haemoglobin.
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Affiliation(s)
- Orit Gat
- Department of Biochemistry and Molecular Genetics, Israel Institute for biological Research, Ness Ziona, Israel.
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The anthrax vaccine adsorbed vaccine generates protective antigen (PA)-Specific CD4+ T cells with a phenotype distinct from that of naive PA T cells. Infect Immun 2008; 76:4538-45. [PMID: 18678674 DOI: 10.1128/iai.00324-08] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cellular immune responses against protective antigen (PA) of Bacillus anthracis in subjects that received the anthrax vaccine adsorbed (AVA) vaccine were examined. Multiple CD4(+) T-cell epitopes within PA were identified by using tetramer-guided epitope mapping. PA-reactive CD4(+) T cells with a CD45RA(-) phenotype were also detected by direct ex vivo staining of peripheral blood mononuclear cells (PBMC) with PA-specific tetramers. Surprisingly, PA-specific T cells were also detected in PBMC of nonvaccinees after a single cycle of in vitro PA stimulation. However, PA-reactive CD4(+) T cells in nonvaccinees occurred at lower frequencies than those in vaccinees. The majority of PA-reactive T cells from nonvaccinees were CD45RA(+) and exhibited a Th0/Th1 cytokine profile. In contrast, phenotyping and cytokine profile analyses of PA-reactive CD4(+) T cells from vaccinees indicated that vaccination leads to commitment of PA-reactive T cells to a Th2 lineage, including generation of PA-specific, pre-Th2 central memory T cells. These results demonstrate that the current AVA vaccine is effective in skewing the development of PA CD4(+) T cells to the Th2 lineage. The data also demonstrated the feasibility of using class II tetramers to analyze CD4(+) cell responses and lineage development after vaccination.
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Recombinant Bacillus anthracis spore proteins enhance protection of mice primed with suboptimal amounts of protective antigen. Vaccine 2008; 26:4927-39. [PMID: 18657585 DOI: 10.1016/j.vaccine.2008.07.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 06/24/2008] [Accepted: 07/08/2008] [Indexed: 11/24/2022]
Abstract
Inactivated Bacillus anthracis spores given with protective antigen (PA) contribute to immunity against anthrax in several animal models. Antiserum raised against whole irradiated B. anthracis spores has been shown to have anti-germination and opsonic activities in vitro. Based on these observations, we hypothesized that surface-exposed spore proteins might serve as supplemental components of a PA-based anthrax vaccine. The protective anti-spore serum was tested for reactivity with recombinant forms of 30 proteins known, or believed to be, present within the B. anthracis exosporium. Eleven of those proteins were reactive with this antiserum, and, subsequently a subset of this group was used to generate rabbit polyclonal antibodies. These sera were evaluated for recognition of the immunogens on intact spores generated from Sterne strain, as well as from an isogenic mutant lacking the spore surface protein Bacillus collagen-like antigen (BclA). The data were consistent with the notion that the antigens in question were located beneath BclA on the basal surface of the exosporium. A/J mice immunized with either the here-to-for hypothetical protein p5303 or the structural protein BxpB, each in combination with subprotective levels of PA, showed enhanced protection against subcutaneous spore challenge. While neither anti-BxpB or anti-p5303 antibodies reduced the rate of spore germination in vitro, both caused increased uptake and lead to a higher rate of destruction by phagocytic cells. We conclude that by facilitating more efficient phagocytic clearance of spores, antibodies against individual exosporium components can contribute to protection against B. anthracis infection.
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Strategies for the development of vaccines conferring broad-spectrum protection. Int J Med Microbiol 2008; 298:379-95. [DOI: 10.1016/j.ijmm.2008.01.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2007] [Revised: 11/07/2007] [Accepted: 01/14/2008] [Indexed: 11/21/2022] Open
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Saccharides cross-reactive with Bacillus anthracis spore glycoprotein as an anthrax vaccine component. Proc Natl Acad Sci U S A 2008; 105:8709-12. [PMID: 18562275 DOI: 10.1073/pnas.0803897105] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacillus anthracis is a spore-forming bacterium that causes anthrax in humans and in other mammals. The glycoprotein BclA (Bacillus collagen-like protein of anthracis) is a major constituent of the exosporium, the outermost surface of B. anthracis spores. The glycosyl part of BclA is an oligosaccharide composed of 2-O-methyl-4-(3-hydroxy-3-methylbutanamido)-4,6-dideoxy-d-glucose, referred to as anthrose, and three rhamnose residues. A structure similar to anthrose, 4-(3-hydroxy-3-methylbutanamido)-4,6-dideoxy-d-glucose is found in the side chain of the capsular polysaccharide (CPS) of Shewanella spp. MR-4. Under certain growth conditions the bacteria produce a variant CPS lacking one methyl group on the hydroxybutyrate, 4-(3-hydroxybutanamido)-4,6-dideoxy-d-glucose. Contrary to anthrose, neither of the Shewanella CPSs is 2-O methylated. Here, we report that both Shewanella CPS variants react with anti-B. anthracis spore sera. We also found that these antisera reacted with flagellae of Pseudomonas syringae, reported to be glycosylated with a similar terminal saccharide, 4-(3-hydroxybutanamido)-4,6-dideoxy-2-O-methyl-d-glucose. Sera produced by immunization with Shewanella or P. syringae cells bound to B. anthracis spores but not to Bacillus cereus spores in a fluorescent microscopy assay. These experiments show that methylation of the anthrose at the O-2 of the sugar ring and at the C-3 of 3-hydroxybutyrate are not essential for induction of cross-reactive antibodies. We report the preparation, characterization, and antibody responses to protein conjugates of the two variants of Shewanella CPS. Both conjugates induced antibodies that bound to both Shewanella CPS variants by ELISA and to B. anthracis spores, as detected by fluorescent microscopy. We propose the use of Shewanella CPS conjugates as a component of an anthrax vaccine.
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Detoxified lethal toxin as a potential mucosal vaccine against anthrax. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2008; 15:612-6. [PMID: 18256208 DOI: 10.1128/cvi.00402-07] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The nontoxic mutant lethal factor (mLF; which has the E687C substitution) and functional protective antigen (PA63) of Bacillus anthracis were evaluated for their use as mucosal vaccines against anthrax in A/J mice. Intranasal vaccination of three doses of 30 microg of mLF or 60 microg of PA63 elicited significant serum and mucosal antibody responses, with anthrax lethal toxin-neutralizing titers of 40 and 60 in immune sera, respectively. However, only 30% and 60% of the vaccinated animals in the two groups could survive a challenge with 100 times the 50% lethal dose of B. anthracis Sterne spores, respectively. In contrast, vaccination with three doses of the combination of 30 microg of mLF and 60 microg of PA63, the detoxified lethal toxin, elicited antibody responses against LF and PA significantly higher than those elicited after vaccination with mLF or PA63 individually by use of the same dose and schedule. Vaccination with the detoxified lethal toxin resulted in significantly higher lethal toxin-neutralizing antibody titers in sera (titer, 90). Animals vaccinated with three doses of the detoxified lethal toxin were completely protected against the spore challenge. The data suggest that mLF and PA63 have a mutual enhancement effect for evoking systemic and mucosal immune responses and that the detoxified lethal toxin can be used as an efficient mucosal vaccine against anthrax.
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