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Kelly SM, Larsen KR, Darling R, Petersen AC, Bellaire BH, Wannemuehler MJ, Narasimhan B. Single-dose combination nanovaccine induces both rapid and durable humoral immunity and toxin neutralizing antibody responses against Bacillus anthracis. Vaccine 2021; 39:3862-3870. [PMID: 34090702 DOI: 10.1016/j.vaccine.2021.05.077] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/24/2021] [Accepted: 05/23/2021] [Indexed: 12/11/2022]
Abstract
Bacillus anthracis, the causative agent of anthrax, continues to be a prominent biological warfare and bioterrorism threat. Vaccination is likely to remain the most effective and user-friendly public health measure to counter this threat in the foreseeable future. The commercially available AVA BioThrax vaccine has a number of shortcomings where improvement would lead to a more practical and effective vaccine for use in the case of an exposure event. Identification of more effective adjuvants and novel delivery platforms is necessary to improve not only the effectiveness of the anthrax vaccine, but also enhance its shelf stability and ease-of-use. Polyanhydride particles have proven to be an effective platform at adjuvanting the vaccine-associated adaptive immune response as well as enhancing stability of encapsulated antigens. Another class of adjuvants, the STING pathway-targeting cyclic dinucleotides, have proven to be uniquely effective at inducing a beneficial inflammatory response that leads to the rapid induction of high titer antibodies post-vaccination capable of providing protection against bacterial pathogens. In this work, we evaluate the individual contributions of cyclic di-GMP (CDG), polyanhydride nanoparticles, and a combination thereof towards inducing neutralizing antibody (nAb) against the secreted protective antigen (PA) from B. anthracis. Our results show that the combination nanovaccine elicited rapid, high titer, and neutralizing IgG anti-PA antibody following single dose immunization that persisted for at least 108 DPI.
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Affiliation(s)
- Sean M Kelly
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States; Nanovaccine Institute, Ames, IA, United States
| | - Kristina R Larsen
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, United States; Interdepartmental Microbiology Program, Iowa State University, Ames, IA, United States
| | - Ross Darling
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, United States
| | - Andrew C Petersen
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, United States
| | - Bryan H Bellaire
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, United States; Interdepartmental Microbiology Program, Iowa State University, Ames, IA, United States; Nanovaccine Institute, Ames, IA, United States
| | - Michael J Wannemuehler
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, United States; Nanovaccine Institute, Ames, IA, United States.
| | - Balaji Narasimhan
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, United States; Nanovaccine Institute, Ames, IA, United States.
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Jeon JH, Kim YH, Kim KA, Kim YR, Woo SJ, Choi YJ, Rhie GE. A putative exosporium lipoprotein GBAA0190 of Bacillus anthracis as a potential anthrax vaccine candidate. BMC Immunol 2021; 22:20. [PMID: 33743606 PMCID: PMC7981958 DOI: 10.1186/s12865-021-00414-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 03/10/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bacillus ancthracis causes cutaneous, pulmonary, or gastrointestinal forms of anthrax. B. anthracis is a pathogenic bacterium that is potentially to be used in bioterrorism because it can be produced in the form of spores. Currently, protective antigen (PA)-based vaccines are being used for the prevention of anthrax, but it is necessary to develop more safe and effective vaccines due to their prolonged immunization schedules and adverse reactions. METHODS We selected the lipoprotein GBAA0190, a potent inducer of host immune response, present in anthrax spores as a novel potential vaccine candidate. Then, we evaluated its immune-stimulating activity in the bone marrow-derived macrophages (BMDMs) using enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. Protective efficacy of GBAA0190 was evaluated in the guinea pig (GP) model. RESULTS The recombinant GBAA0190 (r0190) protein induced the expression of various inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein-1α (MIP-1α) in the BMDMs. These immune responses were mediated through toll-like receptor 1/2 via activation of mitogen-activated protein (MAP) kinase and Nuclear factor-κB (NF-κB) pathways. We demonstrated that not only immunization of r0190 alone, but also combined immunization with r0190 and recombinant PA showed significant protective efficacy against B. anthracis spore challenges in the GP model. CONCLUSIONS Our results suggest that r0190 may be a potential target for anthrax vaccine.
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Affiliation(s)
- Jun Ho Jeon
- Division of High-risk Pathogens, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Cheongju, 28159, Republic of Korea
| | - Yeon Hee Kim
- Division of High-risk Pathogens, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Cheongju, 28159, Republic of Korea
| | - Kyung Ae Kim
- Division of High-risk Pathogens, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Cheongju, 28159, Republic of Korea
| | - Yu-Ri Kim
- Division of High-risk Pathogens, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Cheongju, 28159, Republic of Korea
| | - Sun-Je Woo
- Division of High-risk Pathogens, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Cheongju, 28159, Republic of Korea
| | - Ye Jin Choi
- Division of High-risk Pathogens, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Cheongju, 28159, Republic of Korea
| | - Gi-Eun Rhie
- Division of High-risk Pathogens, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Cheongju, 28159, Republic of Korea.
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Park DB, Ahn BE, Son H, Lee YR, Kim YR, Jo SK, Chun JH, Yu JY, Choi MM, Rhie GE. Construction of a bivalent vaccine against anthrax and smallpox using the attenuated vaccinia virus KVAC103. BMC Microbiol 2021; 21:76. [PMID: 33685392 PMCID: PMC7938549 DOI: 10.1186/s12866-021-02121-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 02/09/2021] [Indexed: 11/10/2022] Open
Abstract
Background Anthrax and smallpox are high-risk infectious diseases, and considered as potential agents for bioterrorism. To develop an effective countermeasure for these diseases, we constructed a bivalent vaccine against both anthrax and smallpox by integrating a gene encoding protective antigen (PA) of Bacillus anthracis to the genome of the attenuated vaccinia virus strain, KVAC103. Results Immunization with this bivalent vaccine induced antibodies against both PA and vaccinia virus in a mouse model. We also observed that the efficacy of this vaccine can be enhanced by combined immunization with immunoadjuvant-expressing KVAC103. Mouse groups co-immunized with PA-expressing KVAC103 and either interleukin-15 (IL-15) or cholera toxin subunit A (CTA1)-expressing KVAC103 showed increased anti-PA IgG titer and survival rate against B. anthracis spore challenge compared to the group immunized with PA-expressing KVAC103 alone. Conclusions We demonstrated that the attenuated smallpox vaccine KVAC103 is an available platform for a multivalent vaccine and co-immunization of immunoadjuvants can improve vaccine performance. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02121-5.
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Affiliation(s)
- Deok Bum Park
- Division of High-risk Pathogens, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Cheongju, South Korea.,Present address: Forensic DNA Division, Gwangju Institute, National Forensic Service, Jeonnam, South Korea
| | - Bo-Eun Ahn
- Division of High-risk Pathogens, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Cheongju, South Korea
| | - Hosun Son
- Division of Vaccine Research, Korea National Institute of Health, Korea Centers for Disease Control and Prevention, Cheongju, South Korea
| | - Young-Ran Lee
- Division of High-risk Pathogens, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Cheongju, South Korea.,Present address: Convergence Bioceramic Materials Center, Korea Institute of Ceramic Engineering and Technology, Cheongju, South Korea
| | - Yu-Ri Kim
- Division of High-risk Pathogens, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Cheongju, South Korea
| | - Su Kyoung Jo
- Division of High-risk Pathogens, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Cheongju, South Korea
| | - Jeong-Hoon Chun
- Division of High-risk Pathogens, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Cheongju, South Korea
| | - Jae-Yon Yu
- Division of High-risk Pathogens, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Cheongju, South Korea
| | - Myung-Min Choi
- Division of High-risk Pathogens, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Cheongju, South Korea
| | - Gi-Eun Rhie
- Division of High-risk Pathogens, Bureau of Infectious Disease Diagnosis Control, Korea Disease Control and Prevention Agency, Cheongju, South Korea.
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Manish M, Verma S, Kandari D, Kulshreshtha P, Singh S, Bhatnagar R. Anthrax prevention through vaccine and post-exposure therapy. Expert Opin Biol Ther 2020; 20:1405-1425. [DOI: 10.1080/14712598.2020.1801626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Manish Manish
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Shashikala Verma
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | - Divya Kandari
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Parul Kulshreshtha
- Department of Zoology, Shivaji College, University of Delhi, Delhi, India
| | - Samer Singh
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
- Department of Microbial Biotechnology, Panjab University, Chandigarh, India
| | - Rakesh Bhatnagar
- Laboratory of Molecular Biology and Genetic Engineering, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
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Savransky V, Ionin B, Reece J. Current Status and Trends in Prophylaxis and Management of Anthrax Disease. Pathogens 2020; 9:E370. [PMID: 32408493 PMCID: PMC7281134 DOI: 10.3390/pathogens9050370] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/29/2020] [Accepted: 05/07/2020] [Indexed: 12/30/2022] Open
Abstract
Bacillus anthracis has been identified as a potential military and bioterror agent as it is relatively simple to produce, with spores that are highly resilient to degradation in the environment and easily dispersed. These characteristics are important in describing how anthrax could be used as a weapon, but they are also important in understanding and determining appropriate prevention and treatment of anthrax disease. Today, anthrax disease is primarily enzootic and found mostly in the developing world, where it is still associated with considerable mortality and morbidity in humans and livestock. This review article describes the spectrum of disease caused by anthrax and the various prevention and treatment options. Specifically we discuss the following; (1) clinical manifestations of anthrax disease (cutaneous, gastrointestinal, inhalational and intravenous-associated); (2) immunology of the disease; (3) an overview of animal models used in research; (4) the current World Health Organization and U.S. Government guidelines for investigation, management, and prophylaxis; (5) unique regulatory approaches to licensure and approval of anthrax medical countermeasures; (6) the history of vaccination and pre-exposure prophylaxis; (7) post-exposure prophylaxis and disease management; (8) treatment of symptomatic disease through the use of antibiotics and hyperimmune or monoclonal antibody-based antitoxin therapies; and (9) the current landscape of next-generation product candidates under development.
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Affiliation(s)
- Vladimir Savransky
- Emergent BioSolutions Inc., 300 Professional Drive, Gaithersburg, MD 20879, USA; (B.I.); (J.R.)
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Kondakova OA, Nikitin NA, Evtushenko EA, Ryabchevskaya EM, Atabekov JG, Karpova OV. Vaccines against anthrax based on recombinant protective antigen: problems and solutions. Expert Rev Vaccines 2019; 18:813-828. [PMID: 31298973 DOI: 10.1080/14760584.2019.1643242] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Introduction: Anthrax is a dangerous bio-terror agent because Bacillus anthracis spores are highly resilient and can be easily aerosolized and disseminated. There is a threat of deliberate use of anthrax spores aerosol that could lead to serious fatal diseases outbreaks. Existing control measures against inhalation form of the disease are limited. All of this has provided an impetus to the development of new generation vaccines. Areas сovered: This review is devoted to challenges and achievements in the design of vaccines based on the anthrax recombinant protective antigen (rPA). Scientific databases have been searched, focusing on causes of PA instability and solutions to this problem, including new approaches of rPA expression, novel rPA-based vaccines formulations as well as the simultaneous usage of PA with other anthrax antigens. Expert opinion: PA is a central anthrax toxin component, playing a key role in the defense against encapsulated and unencapsulated strains. Subunit rPA-based vaccines have a good safety and protective profile. However, there are problems of PA instability that are greatly enhanced when using aluminum adjuvants. New adjuvant compositions, dry formulations and resistant to proteolysis and deamidation mutant PA forms can help to handle this issue. Devising a modern anthrax vaccine requires huge efforts.
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Affiliation(s)
- Olga A Kondakova
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
| | - Nikolai A Nikitin
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
| | - Ekaterina A Evtushenko
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
| | - Ekaterina M Ryabchevskaya
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
| | - Joseph G Atabekov
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
| | - Olga V Karpova
- a Department of Virology, Faculty of Biology, Lomonosov Moscow State University , Moscow , Russian Federation
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Ahn BE, Bae HW, Lee HR, Woo SJ, Park OK, Jeon JH, Park J, Rhie GE. A therapeutic human antibody against the domain 4 of the Bacillus anthracis protective antigen shows protective efficacy in a mouse model. Biochem Biophys Res Commun 2018; 509:611-616. [PMID: 30606479 DOI: 10.1016/j.bbrc.2018.12.146] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 12/20/2018] [Indexed: 01/19/2023]
Abstract
Since Bacillus anthracis is a high-risk pathogen and a potential tool for bioterrorism, numerous therapeutic methods including passive immunization have been actively developed. Using a human monoclonal antibody phage display library, we screened new therapeutic antibodies for anthrax infection against protective antigen (PA) of B. anthracis. Among 5 selected clones of antibodies based on enzyme-linked immunosorbent assay (ELISA) results, 7B1 showed neutralizing activity to anthrax lethal toxin (LT) by inhibiting binding of the domain 4 of PA (PD4) to its cellular receptors. Through light chain shuffling process, we improved the productivity of 7B1 up to 25 folds. The light chain shuffled 7B1 antibody showed protective activity against LT both in vitro and in vivo. Furthermore, the antibody also conferred protection of mice from 3 × LD50 challenges of fully virulent anthrax spores. Our result expands the possibility of developing a new therapeutic antibody for anthrax cure.
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Affiliation(s)
- Bo-Eun Ahn
- Division of High-risk Pathogens, Center for Laboratory Control of Infectious Diseases, Korea Centers for Disease Control and Prevention, Cheongju, 28159, South Korea
| | - Hee-Won Bae
- Division of High-risk Pathogens, Center for Laboratory Control of Infectious Diseases, Korea Centers for Disease Control and Prevention, Cheongju, 28159, South Korea
| | - Hae-Ri Lee
- Division of High-risk Pathogens, Center for Laboratory Control of Infectious Diseases, Korea Centers for Disease Control and Prevention, Cheongju, 28159, South Korea
| | - Sun-Je Woo
- Division of High-risk Pathogens, Center for Laboratory Control of Infectious Diseases, Korea Centers for Disease Control and Prevention, Cheongju, 28159, South Korea
| | - Ok-Kyu Park
- Division of High-risk Pathogens, Center for Laboratory Control of Infectious Diseases, Korea Centers for Disease Control and Prevention, Cheongju, 28159, South Korea
| | - Jun Ho Jeon
- Division of High-risk Pathogens, Center for Laboratory Control of Infectious Diseases, Korea Centers for Disease Control and Prevention, Cheongju, 28159, South Korea
| | - Jungchan Park
- Department of Bioscience and Biotechnology, Hankuk University of Foreign Studies, Yongin, 17035, South Korea
| | - Gi-Eun Rhie
- Division of High-risk Pathogens, Center for Laboratory Control of Infectious Diseases, Korea Centers for Disease Control and Prevention, Cheongju, 28159, South Korea.
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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: 1.4] [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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Pavan ME, Pavan EE, Cairó FM, Pettinari MJ. Expression and refolding of the protective antigen of Bacillus anthracis: A model for high-throughput screening of antigenic recombinant protein refolding. Rev Argent Microbiol 2016; 48:5-14. [PMID: 26777581 DOI: 10.1016/j.ram.2015.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Revised: 09/17/2015] [Accepted: 10/21/2015] [Indexed: 10/22/2022] Open
Abstract
Bacillus anthracis protective antigen (PA) is a well known and relevant immunogenic protein that is the basis for both anthrax vaccines and diagnostic methods. Properly folded antigenic PA is necessary for these applications. In this study a high level of PA was obtained in recombinant Escherichia coli. The protein was initially accumulated in inclusion bodies, which facilitated its efficient purification by simple washing steps; however, it could not be recognized by specific antibodies. Refolding conditions were subsequently analyzed in a high-throughput manner that enabled nearly a hundred different conditions to be tested simultaneously. The recovery of the ability of PA to be recognized by antibodies was screened by dot blot using a coefficient that provided a measure of properly refolded protein levels with a high degree of discrimination. The best refolding conditions resulted in a tenfold increase in the intensity of the dot blot compared to the control. The only refolding additive that consistently yielded good results was L-arginine. The statistical analysis identified both cooperative and negative interactions between the different refolding additives. The high-throughput approach described in this study that enabled overproduction, purification and refolding of PA in a simple and straightforward manner, can be potentially useful for the rapid screening of adequate refolding conditions for other overexpressed antigenic proteins.
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Affiliation(s)
- María Elisa Pavan
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina; Biochemiq S.A., Laboratorio de Biología Molecular, Buenos Aires, Argentina
| | - Esteban Enrique Pavan
- Laboratorio di Tecnologie Biomediche, Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Italy
| | - Fabián Martín Cairó
- Biochemiq S.A., Laboratorio de Biología Molecular, Buenos Aires, Argentina; Facultad de Ciencias Veterinarias, UBA, Argentina
| | - María Julia Pettinari
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina; IQUIBICEN, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.
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Palmer J, Bell M, Darko C, Barnewall R, Keane-Myers A. Protein- and DNA-based anthrax toxin vaccines confer protection in guinea pigs against inhalational challenge with Bacillus cereus G9241. Pathog Dis 2014; 72:138-42. [PMID: 25044336 DOI: 10.1111/2049-632x.12204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 06/12/2014] [Accepted: 06/28/2014] [Indexed: 11/29/2022] Open
Abstract
In the past decade, several Bacillus cereus strains have been isolated from otherwise healthy individuals who succumbed to bacterial pneumonia presenting symptoms resembling inhalational anthrax. One strain was indistinguishable from B. cereus G9241, previously cultured from an individual who survived a similar pneumonia-like illness and which was shown to possess a complete set of plasmid-borne anthrax toxin-encoding homologs. The finding that B. cereus G9241 pathogenesis in mice is dependent on pagA1-derived protective antigen (PA) synthesis suggests that an anthrax toxin-based vaccine may be effective against this toxin-encoding B. cereus strain. Dunkin Hartley guinea pigs were immunized with protein- and DNA-based anthrax toxin-based vaccines, immune responses were evaluated and survival rates were calculated after lethal aerosol exposure with B. cereus G9241 spores. Each vaccine induced seroconversion with the protein immunization regimen eliciting significantly higher serum levels of antigen-specific antibodies at the prechallenge time-point compared with the DNA-protein prime-boost immunization schedule. Complete protection against lethal challenge was observed in all groups with a detectable prechallenge serum titer of toxin neutralizing antibodies. For the first time, we demonstrated that the efficacy of fully defined anthrax toxin-based vaccines was protective against lethal B. cereus G9241 aerosol challenge in the guinea pig animal model.
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Affiliation(s)
- John Palmer
- Vaccines and Medical Countermeasures, Biological Defense Research Directorate, Navy Medical Research Center, NMRC-Frederick, Fort Detrick, MD, USA
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