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Viravathana P, Tepp WH, Bradshaw M, Przedpelski A, Barbieri JT, Pellett S. Potency Evaluations of Recombinant Botulinum Neurotoxin A1 Mutants Designed to Reduce Toxicity. Int J Mol Sci 2024; 25:8955. [PMID: 39201641 PMCID: PMC11355004 DOI: 10.3390/ijms25168955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Revised: 08/12/2024] [Accepted: 08/14/2024] [Indexed: 09/02/2024] Open
Abstract
Recombinant mutant holotoxin BoNTs (rBoNTs) are being evaluated as possible vaccines against botulism. Previously, several rBoNTs containing 2-3 amino acid mutations in the light chain (LC) showed significant decreases in toxicity (2.5-million-fold-12.5-million-fold) versus wild-type BoNT/A1, leading to their current exclusion from the Federal Select Agent list. In this study, we added four additional mutations in the receptor-binding domain, translocation domain, and enzymatic cleft to further decrease toxicity, creating 7M rBoNT/A1. Due to poor expression in E. coli, 7M rBoNT/A1 was produced in an endogenous C. botulinum expression system. This protein had higher residual toxicity (LD50: 280 ng/mouse) than previously reported for the catalytically inactive rBoNT/A1 containing only three of the mutations (>10 µg/mouse). To investigate this discrepancy, several additional rBoNT/A1 constructs containing individual sets of amino acid substitutions from 7M rBoNT/A1 and related mutations were also endogenously produced. Similarly to endogenously produced 7M rBoNT/A1, all of the endogenously produced mutants had ~100-1000-fold greater toxicity than what was reported for their original heterologous host counterparts. A combination of mutations in multiple functional domains resulted in a greater but not multiplicative reduction in toxicity. This report demonstrates the impact of production systems on residual toxicity of genetically inactivated rBoNTs.
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Affiliation(s)
- Polrit Viravathana
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - William H. Tepp
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Marite Bradshaw
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Amanda Przedpelski
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Joseph T. Barbieri
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Sabine Pellett
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
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2
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Park W, Park M, Chun J, Hwang J, Kim S, Choi N, Kim SM, Kim S, Jung S, Ko KS, Kweon DH. Delivery of endolysin across outer membrane of Gram-negative bacteria using translocation domain of botulinum neurotoxin. Int J Antimicrob Agents 2024; 64:107216. [PMID: 38795926 DOI: 10.1016/j.ijantimicag.2024.107216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 04/08/2024] [Accepted: 05/20/2024] [Indexed: 05/28/2024]
Abstract
The emergence of multidrug-resistant pathogens has outpaced the development of new antibiotics, leading to renewed interest in endolysins. Endolysins have been investigated as novel biocontrol agents for Gram-positive bacteria. However, their efficacy against Gram-negative species is limited by the barrier presented by their outer membrane, which prevents endolysin access to the peptidoglycan substrate. Here, we used the translocation domain of botulinum neurotoxin to deliver endolysin across the outer membrane of Gram-negative bacteria. The translocation domain selectively interacts with and penetrates membranes composed of anionic lipids, which have been used in nature to deliver various proteins into animal cells. In addition to the botulinum neurotoxin translocation domain, we have fused bacteriophage-derived receptor binding protein to endolysins. This allows the attached protein to efficiently bind to a broad spectrum of Gram-negative bacteria. By attaching these target-binding and translocation machineries to endolysins, we aimed to develop an engineered endolysin with broad-spectrum targeting and enhanced antibacterial activity against Gram-negative species. To validate our strategy, we designed engineered endolysins using two well-known endolysins, T5 and LysPA26, and tested them against 23 strains from six species of Gram-negative bacteria, confirming that our machinery can act broadly. In particular, we observed a 2.32 log reduction in 30 min with only 0.5 µM against an Acinetobacter baumannii isolate. We also used the SpyTag/SpyCatcher system to easily attach target-binding proteins, thereby improving its target-binding ability. Overall, our newly developed endolysin engineering strategy may be a promising approach to control multidrug-resistant Gram-negative bacterial strains.
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Affiliation(s)
- Wonbeom Park
- Department of Integrative Biotechnology, Sungkyunkwan University College of Biotechnology and Bioengineering, Suwon, Republic of Korea
| | - Myungseo Park
- Department of Integrative Biotechnology, Sungkyunkwan University College of Biotechnology and Bioengineering, Suwon, Republic of Korea; Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology (KRICT), Daejeon, Republic of Korea
| | - Jihwan Chun
- Department of Integrative Biotechnology, Sungkyunkwan University College of Biotechnology and Bioengineering, Suwon, Republic of Korea
| | - Jaehyeon Hwang
- Department of Integrative Biotechnology, Sungkyunkwan University College of Biotechnology and Bioengineering, Suwon, Republic of Korea
| | - Suhyun Kim
- Department of Integrative Biotechnology, Sungkyunkwan University College of Biotechnology and Bioengineering, Suwon, Republic of Korea
| | - Nayoon Choi
- Department of Integrative Biotechnology, Sungkyunkwan University College of Biotechnology and Bioengineering, Suwon, Republic of Korea
| | - Soo Min Kim
- Department of Integrative Biotechnology, Sungkyunkwan University College of Biotechnology and Bioengineering, Suwon, Republic of Korea
| | - SeungJoo Kim
- Department of Integrative Biotechnology, Sungkyunkwan University College of Biotechnology and Bioengineering, Suwon, Republic of Korea
| | - Sangwon Jung
- Research Center, MVRIX, Anyang, Republic of Korea
| | - Kwan Soo Ko
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Dae-Hyuk Kweon
- Department of Integrative Biotechnology, Sungkyunkwan University College of Biotechnology and Bioengineering, Suwon, Republic of Korea; Research Center, MVRIX, Anyang, Republic of Korea.
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3
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Gupta S, Pellett S. Recent Developments in Vaccine Design: From Live Vaccines to Recombinant Toxin Vaccines. Toxins (Basel) 2023; 15:563. [PMID: 37755989 PMCID: PMC10536331 DOI: 10.3390/toxins15090563] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/28/2023] [Accepted: 08/31/2023] [Indexed: 09/28/2023] Open
Abstract
Vaccines are one of the most effective strategies to prevent pathogen-induced illness in humans. The earliest vaccines were based on live inoculations with low doses of live or related pathogens, which carried a relatively high risk of developing the disease they were meant to prevent. The introduction of attenuated and killed pathogens as vaccines dramatically reduced these risks; however, attenuated live vaccines still carry a risk of reversion to a pathogenic strain capable of causing disease. This risk is completely eliminated with recombinant protein or subunit vaccines, which are atoxic and non-infectious. However, these vaccines require adjuvants and often significant optimization to induce robust T-cell responses and long-lasting immune memory. Some pathogens produce protein toxins that cause or contribute to disease. To protect against the effects of such toxins, chemically inactivated toxoid vaccines have been found to be effective. Toxoid vaccines are successfully used today at a global scale to protect against tetanus and diphtheria. Recent developments for toxoid vaccines are investigating the possibilities of utilizing recombinant protein toxins mutated to eliminate biologic activity instead of chemically inactivated toxins. Finally, one of the most contemporary approaches toward vaccine design utilizes messenger RNA (mRNA) as a vaccine candidate. This approach was used globally to protect against coronavirus disease during the COVID-19 pandemic that began in 2019, due to its advantages of quick production and scale-up, and effectiveness in eliciting a neutralizing antibody response. Nonetheless, mRNA vaccines require specialized storage and transport conditions, posing challenges for low- and middle-income countries. Among multiple available technologies for vaccine design and formulation, which technology is most appropriate? This review focuses on the considerable developments that have been made in utilizing diverse vaccine technologies with a focus on vaccines targeting bacterial toxins. We describe how advancements in vaccine technology, combined with a deeper understanding of pathogen-host interactions, offer exciting and promising avenues for the development of new and improved vaccines.
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Affiliation(s)
| | - Sabine Pellett
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA;
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Abdolmohammadi Khiav L, Zahmatkesh A. Major pathogenic Clostridia in human and progress toward the clostridial vaccines. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2022; 25:1059-1068. [PMID: 36246067 PMCID: PMC9526890 DOI: 10.22038/ijbms.2022.65518.14417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 07/20/2022] [Indexed: 12/02/2022]
Abstract
The Clostridium genus is composed of a large spectrum of heterogeneous bacteria. They are Gram-positive, mostly mesophilic, and anaerobic spore-forming strains. Clostridia are widely distributed in oxygen-free habitats. They are found principally in the soil and intestines of ruminants as normal flora, but also are the cause of several infections in humans. The infections produced by important species in humans include botulism, tetanus, pseudomembranous colitis, antibiotics-associated diarrhea, and gas gangrene. Immunization with toxoid or bacterin-toxoid or genetically modified or other vaccines is a protective way against clostridial infection. Several experimental or commercial vaccines have been developed worldwide. Although conventional vaccines including toxoid vaccines are very important, the new generation of vaccines is an effective alternative to conventional vaccines. Recent advances have made it possible for new vaccines to increase immunogenicity. This review discusses briefly the important species of clostridia in humans, their toxins structure, and vaccine development and usage throughout the world.
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Affiliation(s)
- Lida Abdolmohammadi Khiav
- Department of Anaerobic Vaccine Research and Production, Specialized Clostridia Research Laboratory, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization, Karaj, Iran
| | - Azadeh Zahmatkesh
- Department of Anaerobic Vaccine Research and Production, Specialized Clostridia Research Laboratory, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization, Karaj, Iran
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5
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Chang MJ, Ollivault-Shiflett M, Schuman R, Ngoc Nguyen S, Kaltashov IA, Bobst C, Rajagopal SP, Przedpelski A, Barbieri JT, Lees A. Genetically detoxified tetanus toxin as a vaccine and conjugate carrier protein. Vaccine 2022; 40:5103-5113. [PMID: 35871872 DOI: 10.1016/j.vaccine.2022.07.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/16/2022] [Accepted: 07/11/2022] [Indexed: 11/16/2022]
Abstract
Tetanus toxoid (TTxd), developed over 100 years ago, is a clinically effective, legacy vaccine against tetanus. Due to the extreme potency of native tetanus toxin, manufacturing and regulatory efforts often focus on TTxd production, standardization, and safety, rather than product modernization. Recently, a genetically detoxified, full-length tetanus toxin protein (8MTT) was reported as a tetanus vaccine alternative to TTxd (Przedpelski et al. mBio, 2020). Here we describe the production of 8MTT in Gor/MetTM E. coli, a strain engineered to have an oxidative cytoplasm, allowing for the expression of soluble, disulfide-bonded proteins. The strain was also designed to efficiently cleave N-terminal methionine, the obligatory start amino acid for E. coli expressed proteins. 8MTT was purified as a soluble protein from the cytoplasm in a two-column protocol to > 99 % purity, yielding 0.5 g of purified 8MTT/liter of fermentation broth with low endotoxin contamination, and antigenic purity of 3500 Lf/mg protein nitrogen. Mouse immunizations showed 8MTT to be an immunogenic vaccine and effective as a carrier protein for peptide and polysaccharide conjugates. These studies validate 8MTT as commercially viable and, unlike the heterogenous tetanus toxoid, a uniform carrier protein for conjugate vaccines. The development of a recombinant, genetically detoxified toxin produced in E. coli aligns the tetanus vaccine with modern manufacturing, regulatory, standardization, and safety requirements.
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Affiliation(s)
- Min-Ju Chang
- Fina Biosolutions LLC, 9430 Key West Ave, Suite 200, Rockville, MD 20850, United States
| | | | - Richard Schuman
- Antibody and Immunoassay Consultants, 9430 Key West Ave, Suite 201, Rockville, MD 20850, United States
| | - Son Ngoc Nguyen
- University of Massachusetts, 240 Thatcher Way, Life Science Laboratories N369, Amherst, MA 01003, United States
| | - Igor A Kaltashov
- University of Massachusetts, 240 Thatcher Way, Life Science Laboratories N369, Amherst, MA 01003, United States
| | - Cedric Bobst
- University of Massachusetts, 240 Thatcher Way, Life Science Laboratories N369, Amherst, MA 01003, United States
| | - Shalini P Rajagopal
- National Institute for Biological Standards and Control, Medicines and Healthcare products Regulatory Agency, Blanche Lane, South Mimms, Potters Bar EN6 3QG, UK
| | - Amanda Przedpelski
- Medical College of Wisconsin, 8701 Watertown Plank Rd., Microbiology and Immunology BSB-2830, Milwaukee, WI 53226, United States
| | - Joseph T Barbieri
- Medical College of Wisconsin, 8701 Watertown Plank Rd., Microbiology and Immunology BSB-2830, Milwaukee, WI 53226, United States
| | - Andrew Lees
- Fina Biosolutions LLC, 9430 Key West Ave, Suite 200, Rockville, MD 20850, United States
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6
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Formation and Maturation of the Phagosome: A Key Mechanism in Innate Immunity against Intracellular Bacterial Infection. Microorganisms 2020; 8:microorganisms8091298. [PMID: 32854338 PMCID: PMC7564318 DOI: 10.3390/microorganisms8091298] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/21/2020] [Accepted: 08/24/2020] [Indexed: 02/07/2023] Open
Abstract
Phagocytosis is an essential mechanism in innate immune defense, and in maintaining homeostasis to eliminate apoptotic cells or microbes, such as Mycobacterium tuberculosis, Salmonella enterica, Streptococcus pyogenes and Legionella pneumophila. After internalizing microbial pathogens via phagocytosis, phagosomes undergo a series of ‘maturation’ steps, to form an increasingly acidified compartment and subsequently fuse with the lysosome to develop into phagolysosomes and effectively eliminate the invading pathogens. Through this mechanism, phagocytes, including macrophages, neutrophils and dendritic cells, are involved in the processing of microbial pathogens and antigen presentation to T cells to initiate adaptive immune responses. Therefore, phagocytosis plays a role in the bridge between innate and adaptive immunity. However, intracellular bacteria have evolved diverse strategies to survive and replicate within hosts. In this review, we describe the sequential stages in the phagocytosis process. We also discuss the immune evasion strategies used by pathogens to regulate phagosome maturation during intracellular bacterial infection, and indicate that these might be used for the development of potential therapeutic strategies for infectious diseases.
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7
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Potency and stability of a trivalent, catalytically inactive vaccine against botulinum neurotoxin serotypes C, E and F (triCEF). Toxicon 2020; 176:67-76. [PMID: 32032587 DOI: 10.1016/j.toxicon.2020.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 01/18/2020] [Accepted: 02/03/2020] [Indexed: 01/13/2023]
Abstract
Botulism is an acute neuroparalytic affliction of the motor and autonomic neurons caused by the toxins produced from Clostridium botulinum and related bacterial strains. The botulinum neurotoxins, or BoNTs, consist of a phylogenetically diverse group of highly potent protein toxins. Current medical interventions for confirmed cases of botulism are limited to immediate administration of antitoxins and respiratory support. There is currently no licensed vaccine against botulism in the United States. The most widely distributed botulism vaccine was a pentavalent BoNT toxoid (PBT) against serotypes A-E administered until 2011 under an investigational new drug license. A binary vaccine composed of the recombinant, non-toxic, receptor binding domains (RBD) of serotypes/A1 and/B1 has completed a phase II clinical trial, but has yet to attain full licensure. We have previously published data demonstrating catalytically inactive, full length botulinum neurotoxin holoproteins (ciBoNT HPs) against serotypes/A1,/B1,/C1,/E1 and/F1 provide equivalent or superior potency against parental and dissimilar subtype toxins as compared the RBD vaccines. Here we describe the consistent potencies of the three independent lots each of ciBoNT/C1,/E1, and/F1 HPs against substantial monovalent challenges of the parental toxins. We also present data that a trivalent formulation of ciBoNT/C1,/E1 and/F1 (triCEF) maintains potency against both monovalent and polyvalent toxin challenges when stored as an adjuvanted vaccine at 4-8 °C for up to 2 years.
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8
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Monoclonal Antibody Combinations Prevent Serotype A and Serotype B Inhalational Botulism in a Guinea Pig Model. Toxins (Basel) 2019; 11:toxins11040208. [PMID: 30959899 PMCID: PMC6520708 DOI: 10.3390/toxins11040208] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 03/29/2019] [Accepted: 03/30/2019] [Indexed: 11/16/2022] Open
Abstract
Botulinum neurotoxins (BoNT) are some of the most toxic proteins known, with a human LD50 of ~1 ng/kg. Equine antitoxin has a half-life in circulation of less than 1 day and is limited to a treatment rather than a prevention indication. The development of monoclonal antibodies (mAbs) may represent an alternative therapeutic option that can be produced at high quantities and of high quality and with half-lives of >10 days. Two different three mAb combinations are being developed that specifically neutralize BoNT serotypes A (BoNT/A) and B (BoNT/B). We investigated the pharmacokinetics of the anti-BoNT/A and anti-BoNT/B antibodies in guinea pigs (Cavia porcellus) and their ability to protect guinea pigs against an aerosol challenge of BoNT/A1 or BoNT/B1. Each antibody exhibited dose-dependent exposure and reached maximum circulating concentrations within 48 h post intraperitoneal or intramuscular injection. A single intramuscular dose of the three mAb combination protected guinea pigs against an aerosol challenge dose of 93 LD50 of BoNT/A1 and 116 LD50 of BoNT/B1 at 48 h post antibody administration. These mAbs are effective in preventing botulism after an aerosol challenge of BoNT/A1 and BoNT/B1 and may represent an alternative to vaccination to prevent type A or B botulism in those at risk of BoNT exposure.
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9
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Webb RP. Engineering of Botulinum Neurotoxins for Biomedical Applications. Toxins (Basel) 2018; 10:toxins10060231. [PMID: 29882791 PMCID: PMC6024800 DOI: 10.3390/toxins10060231] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/01/2018] [Accepted: 06/05/2018] [Indexed: 01/15/2023] Open
Abstract
Botulinum neurotoxins (BoNTs) have been used as therapeutic agents in the clinical treatment of a wide array of neuromuscular and autonomic neuronal transmission disorders. These toxins contain three functional domains that mediate highly specific neuronal cell binding, internalization and cytosolic delivery of proteolytic enzymes that cleave proteins integral to the exocytosis of neurotransmitters. The exceptional cellular specificity, potency and persistence within the neuron that make BoNTs such effective toxins, also make them attractive models for derivatives that have modified properties that could potentially expand their therapeutic repertoire. Advances in molecular biology techniques and rapid DNA synthesis have allowed a wide variety of novel BoNTs with alternative functions to be assessed as potential new classes of therapeutic drugs. This review examines how the BoNTs have been engineered in an effort to produce new classes of therapeutic molecules to address a wide array of disorders.
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Affiliation(s)
- Robert P Webb
- The Division of Molecular and Translational Sciences, United States Army Medical Research Institute for Infectious Diseases, Fort Detrick, MD 21702, USA.
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10
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Davies JR, Hackett GS, Liu SM, Acharya KR. High resolution crystal structures of the receptor-binding domain of Clostridium botulinum neurotoxin serotypes A and FA. PeerJ 2018; 6:e4552. [PMID: 29576992 PMCID: PMC5866713 DOI: 10.7717/peerj.4552] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 03/08/2018] [Indexed: 01/12/2023] Open
Abstract
The binding specificity of botulinum neurotoxins (BoNTs) is primarily a consequence of their ability to bind to multiple receptors at the same time. BoNTs consist of three distinct domains, a metalloprotease light chain (LC), a translocation domain (HN) and a receptor-binding domain (HC). Here we report the crystal structure of HC/FA, complementing an existing structure through the modelling of a previously unresolved loop which is important for receptor-binding. Our HC/FA structure also contains a previously unidentified disulphide bond, which we have also observed in one of two crystal forms of HC/A1. This may have implications for receptor-binding and future recombinant toxin production.
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Affiliation(s)
- Jonathan R Davies
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | | | - Sai Man Liu
- Ipsen Bioinnovation Limited, Abingdon, United Kingdom
| | - K Ravi Acharya
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
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11
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Yu CH, Song DH, Choi JY, Joe HE, Jeong WH, Hur GH, Shin YK, Jeong ST. A mutated recombinant subunit vaccine protects mice and guinea pigs against botulinum type A intoxication. Hum Vaccin Immunother 2018; 14:329-336. [PMID: 29140753 PMCID: PMC5806659 DOI: 10.1080/21645515.2017.1405201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 10/17/2017] [Accepted: 11/09/2017] [Indexed: 02/08/2023] Open
Abstract
Botulinum neurotoxins (BoNTs) are the most potent toxins to mammals. A toxoid vaccine was previously used for prevention of botulinum intoxication; however, this vaccine is no longer available. Currently, no approved botulinum vaccines are available from the Food and Drug Administration (FDA). Recently, a recombinant host cell receptor-binding subunit created for use as a potential vaccine completed phase 2 clinical trials. The current study designed a vaccine candidate against BoNT type A (BoNT/A) using a structural design. Our vaccine candidate was the BoNT/A heavy chain C-terminal region (HCR) that contained the point mutation BA15 (R1269A) within the ganglioside-binding site. A Biacore affinity test showed that the affinity of BA15 for ganglioside GT1b was 100 times lower than that of the HCR. A SNAP25 cleavage assay revealed that immunized sera blocked SNAP25 cleavage of the BoNT/A toxin via BA15. In an in vivo experiment, mice and guinea pigs immunized with BA15 produced neutralizing antibodies that protected against 3,000 LD50 of BoNT/A. In conclusion, the results of both in vitro and in vivo assays showed that our BA15 vaccine candidate was similar to the recombinant host cell receptor-binding subunit vaccine. The inability of BA15to bind ganglioside shows that BA15 is a potential safe vaccine candidate.
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Affiliation(s)
- Chi Ho Yu
- Agency for Defense Development, Yuseong, Daejeon, Republic of Korea
| | - Dong Hyun Song
- Agency for Defense Development, Yuseong, Daejeon, Republic of Korea
| | - Jun Young Choi
- Abion R&D Institute, Hanhwa Biz-Metro, Guro-gu, Seoul, Republic of Korea
| | - Hae Eun Joe
- Agency for Defense Development, Yuseong, Daejeon, Republic of Korea
| | - Woo Hyeon Jeong
- Agency for Defense Development, Yuseong, Daejeon, Republic of Korea
| | - Gyeung Haeng Hur
- Agency for Defense Development, Yuseong, Daejeon, Republic of Korea
| | - Young Kee Shin
- Department of Pharmacy, College of Pharmacy, Seoul National University, Dajeon, Seoul, Republic of Korea
| | - Seong Tae Jeong
- Agency for Defense Development, Yuseong, Daejeon, Republic of Korea
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12
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Przedpelski A, Tepp WH, Zuverink M, Johnson EA, Pellet S, Barbieri JT. Enhancing toxin-based vaccines against botulism. Vaccine 2018; 36:827-832. [PMID: 29307477 DOI: 10.1016/j.vaccine.2017.12.064] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 01/25/2023]
Abstract
Botulinum neurotoxins (BoNT) are the most toxic proteins for humans. BoNTs are single chain proteins with an N-terminal light chain (LC) and a C-terminal heavy chain (HC). HC comprises a translocation domain (HCN) and a receptor binding domain (HCC). Currently, there are no approved vaccines against botulism. This study tests a recombinant, full-length BoNT/A1 versus LCHCN/A1 and HCC/A1 as vaccine candidates against botulism. Recombinant, full-length BoNT/A1 was detoxified by engineering 3-amino acid mutations (E224A/R363A/Y366F) (M-BoNT/A1) into the LC to eliminate catalytic activity, which reduced toxicity in a mouse model of botulism by >106-fold relative to native BoNT/A1. As a second step to improve vaccine safety, an additional mutation (W1266A) was engineered in the ganglioside binding pocket, resulting in reduced receptor binding, to produce M-BoNT/A1W. M-BoNT/A1W vaccination protected against challenge by 106 LD50 Units of native BoNT/A1, while M-BoNT/A1 or M-BoNT/A1W vaccination equally protected against challenge by native BoNT/A2, a BoNT subtype. Mice vaccinated with M-BoNT/A1W surviving BoNT challenge had dominant antibody responses to the LCHCN domain, but varied antibody responses to HCC. Sera from mice vaccinated with M-BoNT/A1W also neutralized BoNT/A1 action on cultured neuronal cells. The cell- and mouse-based assays measured different BoNT-neutralizing antibodies, where M-BoNT/A1W elicited a strong neutralizing response in both assays. Overall, M-BoNT/A1W, with defects in multiple toxin functions, elicits a potent immune response to BoNT/A challenge as a vaccine strategy against botulism and other toxin-mediated diseases.
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Affiliation(s)
- Amanda Przedpelski
- Medical College of Wisconsin, 8701 W Watertown Plank Rd., Microbiology and Immunology, Milwaukee, WI 53226, United States
| | - William H Tepp
- University of Wisconsin-Madison, 6303 Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706, United States
| | - Madison Zuverink
- Medical College of Wisconsin, 8701 W Watertown Plank Rd., Microbiology and Immunology, Milwaukee, WI 53226, United States
| | - Eric A Johnson
- University of Wisconsin-Madison, 6303 Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706, United States
| | - Sabine Pellet
- University of Wisconsin-Madison, 6303 Microbial Sciences Building, 1550 Linden Dr., Madison, WI 53706, United States
| | - Joseph T Barbieri
- Medical College of Wisconsin, 8701 W Watertown Plank Rd., Microbiology and Immunology, Milwaukee, WI 53226, United States.
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Protein Structure Facilitates High-Resolution Immunological Mapping. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:CVI.00275-17. [PMID: 29046310 DOI: 10.1128/cvi.00275-17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Select agents (SA) pose unique challenges for licensing vaccines and therapies. In the case of toxin-mediated diseases, HHS assigns guidelines for SA use, oversees vaccine and therapy development, and approves animal models and approaches to identify mechanisms for toxin neutralization. In this commentary, we discuss next-generation vaccines and therapies against ricin toxin and botulinum toxin, which are regulated SA toxins that utilize structure-based approaches for countermeasures to guide rapid response to future biothreats.
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Vaccines against Botulism. Toxins (Basel) 2017; 9:toxins9090268. [PMID: 28869493 PMCID: PMC5618201 DOI: 10.3390/toxins9090268] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 08/30/2017] [Accepted: 08/30/2017] [Indexed: 12/16/2022] Open
Abstract
Botulinum neurotoxins (BoNT) cause the flaccid paralysis of botulism by inhibiting the release of acetylcholine from motor neurons. There are seven serotypes of BoNT (A-G), with limited therapies, and no FDA approved vaccine for botulism. An investigational formalin-inactivated penta-serotype-BoNT/A-E toxoid vaccine was used to vaccinate people who are at high risk of contracting botulism. However, this formalin-inactivated penta-serotype-BoNT/A-E toxoid vaccine was losing potency and was discontinued. This article reviews the different vaccines being developed to replace the discontinued toxoid vaccine. These vaccines include DNA-based, viral vector-based, and recombinant protein-based vaccines. DNA-based vaccines include plasmids or viral vectors containing the gene encoding one of the BoNT heavy chain receptor binding domains (HC). Viral vectors reviewed are adenovirus, influenza virus, rabies virus, Semliki Forest virus, and Venezuelan Equine Encephalitis virus. Among the potential recombinant protein vaccines reviewed are HC, light chain-heavy chain translocation domain, and chemically or genetically inactivated holotoxin.
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Entry of Botulinum Neurotoxin Subtypes A1 and A2 into Neurons. Infect Immun 2016; 85:IAI.00795-16. [PMID: 27795365 DOI: 10.1128/iai.00795-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 10/05/2016] [Indexed: 11/20/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are the most toxic proteins for humans but also are common therapies for neurological diseases. BoNTs are dichain toxins, comprising an N-terminal catalytic domain (LC) disulfide bond linked to a C-terminal heavy chain (HC) which includes a translocation domain (HN) and a receptor binding domain (HC). Recently, the BoNT serotype A (BoNT/A) subtypes A1 and A2 were reported to possess similar potencies but different rates of cellular intoxication and pathology in a mouse model of botulism. The current study measured HCA1 and HCA2 entry into rat primary neurons and cultured Neuro2A cells. We found that there were two sequential steps during the association of BoNT/A with neurons. The initial step was ganglioside dependent, while the subsequent step involved association with synaptic vesicles. HCA1 and HCA2 entered the same population of synaptic vesicles and entered cells at similar rates. The primary difference was that HCA2 had a higher degree of receptor occupancy for cells and neurons than HcA1. Thus, HCA2 and HCA1 share receptors and entry pathway but differ in their affinity for receptor. The initial interaction of HCA1 and HCA2 with neurons may contribute to the unique pathologies of BoNT/A1 and BoNT/A2 in mouse models.
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Structural constraints-based evaluation of immunogenic avirulent toxins from Clostridium botulinum C2 and C3 toxins as subunit vaccines. INFECTION GENETICS AND EVOLUTION 2016; 44:17-27. [PMID: 27320793 DOI: 10.1016/j.meegid.2016.06.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 05/26/2016] [Accepted: 06/13/2016] [Indexed: 12/11/2022]
Abstract
Clostridium botulinum (group-III) is an anaerobic bacterium producing C2 and C3 toxins in addition to botulinum neurotoxins in avian and mammalian cells. C2 and C3 toxins are members of bacterial ADP-ribosyltransferase superfamily, which modify the eukaryotic cell surface proteins by ADP-ribosylation reaction. Herein, the mutant proteins with lack of catalytic and pore forming function derived from C2 (C2I and C2II) and C3 toxins were computationally evaluated to understand their structure-function integrity. We have chosen many structural constraints including local structural environment, folding process, backbone conformation, conformational dynamic sub-space, NAD-binding specificity and antigenic determinants for screening of suitable avirulent toxins. A total of 20 avirulent mutants were identified out of 23 mutants, which were experimentally produced by site-directed mutagenesis. No changes in secondary structural elements in particular to α-helices and β-sheets and also in fold rate of all-β classes. Structural stability was maintained by reordered hydrophobic and hydrogen bonding patterns. Molecular dynamic studies suggested that coupled mutations may restrain the binding affinity to NAD(+) or protein substrate upon structural destabilization. Avirulent toxins of this study have stable energetic backbone conformation with a common blue print of folding process. Molecular docking studies revealed that avirulent mutants formed more favorable hydrogen bonding with the side-chain of amino acids near to conserved NAD-binding core, despite of restraining NAD-binding specificity. Thus, structural constraints in the avirulent toxins would determine their immunogenic nature for the prioritization of protein-based subunit vaccine/immunogens to avian and veterinary animals infected with C. botulinum.
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Prathiviraj R, Prisilla A, Chellapandi P. Structure–function discrepancy inClostridium botulinumC3 toxin for its rational prioritization as a subunit vaccine. J Biomol Struct Dyn 2015; 34:1317-29. [DOI: 10.1080/07391102.2015.1078745] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Maslanka SE, Lúquez C, Dykes JK, Tepp WH, Pier CL, Pellett S, Raphael BH, Kalb SR, Barr JR, Rao A, Johnson EA. A Novel Botulinum Neurotoxin, Previously Reported as Serotype H, Has a Hybrid-Like Structure With Regions of Similarity to the Structures of Serotypes A and F and Is Neutralized With Serotype A Antitoxin. J Infect Dis 2015; 213:379-85. [PMID: 26068781 DOI: 10.1093/infdis/jiv327] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 04/16/2015] [Indexed: 01/13/2023] Open
Abstract
Botulism is a potentially fatal paralytic disease caused by the action of botulinum neurotoxin (BoNT) on nerve cells. There are 7 known serotypes (A-G) of BoNT and up to 40 genetic variants. Clostridium botulinum strain IBCA10-7060 was recently reported to produce BoNT serotype B (BoNT/B) and a novel BoNT, designated as BoNT/H. The BoNT gene (bont) sequence of BoNT/H was compared to known bont sequences. Genetic analysis suggested that BoNT/H has a hybrid-like structure containing regions of similarity to the structures of BoNT/A1 and BoNT/F5. This novel BoNT was serologically characterized by the mouse neutralization assay and a neuronal cell-based assay. The toxic effects of this hybrid-like BoNT were completely eliminated by existing serotype A antitoxins, including those contained in multivalent therapeutic antitoxin products that are the mainstay of human botulism treatment.
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Affiliation(s)
| | - Carolina Lúquez
- Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Janet K Dykes
- Centers for Disease Control and Prevention, Atlanta, Georgia
| | - William H Tepp
- Department of Bacteriology, University of Wisconsin-Madison
| | | | - Sabine Pellett
- Department of Bacteriology, University of Wisconsin-Madison
| | - Brian H Raphael
- Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Suzanne R Kalb
- Centers for Disease Control and Prevention, Atlanta, Georgia
| | - John R Barr
- Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Agam Rao
- Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Eric A Johnson
- Department of Bacteriology, University of Wisconsin-Madison
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Anniballi F, Lonati D, Fiore A, Auricchio B, De Medici D, Locatelli CA. New targets in the search for preventive and therapeutic agents for botulism. Expert Rev Anti Infect Ther 2014; 12:1075-86. [PMID: 25089560 DOI: 10.1586/14787210.2014.945917] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Botulism is a severe neuroparalytic disease resulting from exposure to one of the most poisonous toxins to humans. Because of this high potency and the use of toxins as biological weapons, botulism is a public health concern and each case represents an emergency. Current therapy involves respiratory supportive care and anti-toxins administration. As a preventive measure, vaccination against toxins represents an effective strategy but is undesirable due the rarity of botulism and the effectiveness of toxins in treating several neuromuscular disorders. This paper summarizes the current issues in botulism treatment and prevention, highlighting the challenge for future researches.
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Affiliation(s)
- Fabrizio Anniballi
- Department of Veterinary Public Health and Food Safety, National Reference Centre for Botulism, Istituto Superiore di Sanità, Viale Regina Elena, 299 - 00161 Rome, Italy
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Production of recombinant botulism antigens: A review of expression systems. Anaerobe 2014; 28:130-6. [DOI: 10.1016/j.anaerobe.2014.06.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 06/03/2014] [Accepted: 06/03/2014] [Indexed: 11/18/2022]
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