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Dorner MB, Wilking H, Skiba M, Wilk L, Steinberg M, Worbs S, Çeken S, Kaygusuz S, Simon S, Becher F, Mikolajewska A, Kornschober C, Bütler T, Jourdan-Da-Silva N, An der Heiden M, Schaade L, Stark K, Dorner BG, Frank C. A large travel-associated outbreak of iatrogenic botulism in four European countries following intragastric botulinum neurotoxin injections for weight reduction, Türkiye, February to March 2023. Euro Surveill 2023; 28:2300203. [PMID: 37289431 PMCID: PMC10318948 DOI: 10.2807/1560-7917.es.2023.28.23.2300203] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 05/14/2023] [Indexed: 06/09/2023] Open
Abstract
In March 2023, 34 associated cases of iatrogenic botulism were detected in Germany (30 cases), Switzerland (two cases), Austria (one case), and France (one case). An alert was rapidly disseminated via European Union networks and communication platforms (Food- and Waterborne Diseases and Zoonoses Network, EpiPulse, Early Warning and Response System) and the International Health Regulation mechanism; the outbreak was investigated in a European collaboration. We traced sources of the botulism outbreak to treatment of weight loss in Türkiye, involving intragastric injections of botulinum neurotoxin. Cases were traced using a list of patients who had received this treatment. Laboratory investigations of the first 12 German cases confirmed nine cases. The application of innovative and highly sensitive endopeptidase assays was necessary to detect minute traces of botulinum neurotoxin in patient sera. The botulism notification requirement for physicians was essential to detect this outbreak in Germany. The surveillance case definition of botulism should be revisited and inclusion of cases of iatrogenic botulism should be considered as these cases might lack standard laboratory confirmation yet warrant public health action. Any potential risks associated with the use of botulinum neurotoxins in medical procedures need to be carefully balanced with the expected benefits of the procedure.
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Affiliation(s)
- Martin Bernhard Dorner
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Hendrik Wilking
- Department for Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
| | - Martin Skiba
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Laura Wilk
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Maximilian Steinberg
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Sylvia Worbs
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Sabahat Çeken
- General Directorate of Public Health, Ministry of Health, Ankara, Türkiye
| | - Sedat Kaygusuz
- General Directorate of Public Health, Ministry of Health, Ankara, Türkiye
| | - Stéphanie Simon
- Université Paris Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE), Département Médicaments et Technologies pour la Santé (DMTS), SPI, Gif-sur-Yvette, France
| | - François Becher
- Université Paris Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE), Département Médicaments et Technologies pour la Santé (DMTS), SPI, Gif-sur-Yvette, France
| | - Agata Mikolajewska
- Strategy and Incident Response (ZBS7), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | | | - Timo Bütler
- National International Health Regulation (IHR) Focal Point for Switzerland, Swiss Federal Office of Public Health, Division of Communicable Diseases, Bern, Switzerland
| | | | - Maria An der Heiden
- Department for Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
| | - Lars Schaade
- Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
| | - Klaus Stark
- Department for Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
| | - Brigitte Gertrud Dorner
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, Germany
- These authors contributed equally to the work and share the last authorship
| | - Christina Frank
- These authors contributed equally to the work and share the last authorship
- Department for Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
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New approach for the rational selection of markers to identify botulinum toxins. Arch Toxicol 2021; 95:1503-1516. [PMID: 33569691 DOI: 10.1007/s00204-021-02996-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 01/28/2021] [Indexed: 10/22/2022]
Abstract
The application of mass spectrometry (MS) to detect unique peptide markers has been widely employed as a means of identifying bacterial proteins. Botulinum neurotoxins (BoNTs) are bacterial proteins that cause the life-threatening disease botulism. BoNTs are divided into several antigenically distinct serotypes and several dozen subtypes. The toxins' molecular heterogeneity makes their detection highly challenging. In this study, we describe a new LC-MS/MS-based platform for the direct identification of proteins derived from various species and subspecies in a single assay, as exemplified by BoNTs. The platform employs a rational down-selection process through several steps based on a combination of bioinformatics, tryptic digestion, and LC-MS, each leads to the final panel of markers. This approach has been demonstrated for all 8 subtypes of botulinum serotype A (BoNT/A). Ab-independent and Ab-dependent assays were developed based on the identification of 4 rationally selected markers or a combination of some of them, which enables full selectivity coverage. The Ab-independent assay, which is highly simple and rapid, has a sample-to-result turnaround time of approximately 40 min and enables the identification of 500 MsLD50/mL (5 ng/mL) BoNT/A in complex environmental matrices. The Ab-dependent assay, which is based on toxin's specific enrichment, has a turnaround time of 100 min, but enables improved sensitivity (50 MsLD50/mL, 0.5 ng/mL). Both assays were verified and validated using various environmental samples. This approach can easily be expanded to other botulinum serotypes and exhibits the potential for even further extension as a highly multiplexed assay for protein-based toxins, viruses, and organisms.
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Tevell Åberg A, Karlsson I, Hedeland M. Modification and validation of the Endopep-mass spectrometry method for botulinum neurotoxin detection in liver samples with application to samples collected during animal botulism outbreaks. Anal Bioanal Chem 2020; 413:345-354. [PMID: 33119784 PMCID: PMC7806574 DOI: 10.1007/s00216-020-03001-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/29/2020] [Accepted: 10/09/2020] [Indexed: 01/07/2023]
Abstract
Botulinum neurotoxins (BoNTs) are the most potent toxins known and they cause the paralytic disease botulism in humans and animals. In order to diagnose botulism, active BoNT must be detected in biological material. Endopep-MS is a sensitive and selective method for serum samples, based on antibody capture, enzymatic cleavage of target peptides, and detection of cleavage products using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS). In many cases of animal botulism, serum samples are not available or they do not contain detectable amounts of BoNT and liver sampling is an alternative for postmortem examinations. However, the Endopep-MS method is impaired by the inherent protease activity of liver samples. In the presented study, the Endopep-MS method has been successfully modified and validated for analysis of cattle, horse, and avian liver samples, introducing a combination of a salt washing step and a protease inhibitor cocktail. These modifications resulted in a substantial decrease in interfering signals and increase in BoNT-specific signals. This led to a substantial improvement in sensitivity for especially BoNT-C and C/D which are among the most prominent serotypes for animal botulism. Botulism was diagnosed with the new method in liver samples from dead cattle and birds from outbreaks in Sweden. Graphical Abstract.
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Affiliation(s)
- Annica Tevell Åberg
- Department of Chemistry, Environment, and Feed Hygiene, National Veterinary Institute (SVA), 751 89, Uppsala, Sweden.,Department of Medicinal Chemistry, Analytical Pharmaceutical Chemistry, Faculty of Pharmacy, Uppsala University, P.O. Box 574, 751 23, Uppsala, Sweden
| | - Ida Karlsson
- Department of Chemistry, Environment, and Feed Hygiene, National Veterinary Institute (SVA), 751 89, Uppsala, Sweden.,Department of Medicinal Chemistry, Analytical Pharmaceutical Chemistry, Faculty of Pharmacy, Uppsala University, P.O. Box 574, 751 23, Uppsala, Sweden
| | - Mikael Hedeland
- Department of Chemistry, Environment, and Feed Hygiene, National Veterinary Institute (SVA), 751 89, Uppsala, Sweden. .,Department of Medicinal Chemistry, Analytical Pharmaceutical Chemistry, Faculty of Pharmacy, Uppsala University, P.O. Box 574, 751 23, Uppsala, Sweden.
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von Berg L, Stern D, Weisemann J, Rummel A, Dorner MB, Dorner BG. Optimization of SNAP-25 and VAMP-2 Cleavage by Botulinum Neurotoxin Serotypes A-F Employing Taguchi Design-of-Experiments. Toxins (Basel) 2019; 11:toxins11100588. [PMID: 31614566 PMCID: PMC6832249 DOI: 10.3390/toxins11100588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/01/2019] [Accepted: 10/09/2019] [Indexed: 11/17/2022] Open
Abstract
The detection of catalytically active botulinum neurotoxins (BoNTs) can be achieved by monitoring the enzymatic cleavage of soluble NSF (N-ethylmaleimide-sensitive-factor) attachment protein receptor (SNARE) proteins by the toxins’ light chains (LC) in cleavage-based assays. Thus, for sensitive BoNT detection, optimal cleavage conditions for the clinically relevant A–F serotypes are required. Until now, a systematic evaluation of cleavage conditions for the different BoNT serotypes is still lacking. To address this issue, we optimized cleavage conditions for BoNT/A–F using the Taguchi design-of-experiments (DoE) method. To this aim, we analyzed the influence of buffer composition (pH, Zn2+, DTT (dithiothreitol), NaCl) as well as frequently used additives (BSA (bovine serum albumin), Tween 20, trimethylamine N-oxide (TMAO)) on BoNT substrate cleavage. We identified major critical factors (DTT, Zn2+, TMAO) and were able to increase the catalytic efficiency of BoNT/B, C, E, and F when compared to previously described buffers. Moreover, we designed a single consensus buffer for the optimal cleavage of all tested serotypes. Our optimized buffers are instrumental to increase the sensitivity of cleavage-based assays for BoNT detection. Furthermore, the application of the Taguchi DoE approach shows how the method helps to rationally improve enzymatic assays.
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Affiliation(s)
- Laura von Berg
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany.
| | - Daniel Stern
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany.
| | - Jasmin Weisemann
- Institut für Toxikologie, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
| | - Andreas Rummel
- Institut für Toxikologie, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
| | - Martin Bernhard Dorner
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany.
| | - Brigitte Gertrud Dorner
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany.
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von Berg L, Stern D, Pauly D, Mahrhold S, Weisemann J, Jentsch L, Hansbauer EM, Müller C, Avondet MA, Rummel A, Dorner MB, Dorner BG. Functional detection of botulinum neurotoxin serotypes A to F by monoclonal neoepitope-specific antibodies and suspension array technology. Sci Rep 2019; 9:5531. [PMID: 30940836 PMCID: PMC6445094 DOI: 10.1038/s41598-019-41722-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 03/15/2019] [Indexed: 12/26/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are the most potent toxins known and cause the life threatening disease botulism. Sensitive and broad detection is extremely challenging due to the toxins' high potency and molecular heterogeneity with several serotypes and more than 40 subtypes. The toxicity of BoNT is mediated by enzymatic cleavage of different synaptic proteins involved in neurotransmitter release at serotype-specific cleavage sites. Hence, active BoNTs can be monitored and distinguished in vitro by detecting their substrate cleavage products. In this work, we developed a comprehensive panel of monoclonal neoepitope antibodies (Neo-mAbs) highly specific for the newly generated N- and/or C-termini of the substrate cleavage products of BoNT serotypes A to F. The Neo-mAbs were implemented in a set of three enzymatic assays for the simultaneous detection of two BoNT serotypes each by monitoring substrate cleavage on colour-coded magnetic Luminex-beads. For the first time, all relevant serotypes could be detected in parallel by a routine in vitro activity assay in spiked serum and food samples yielding excellent detection limits in the range of the mouse bioassay or better (0.3-80 pg/mL). Therefore, this work represents a major step towards the replacement of the mouse bioassay for botulism diagnostics.
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Affiliation(s)
- Laura von Berg
- Biological Toxins (ZBS 3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, 13353, Germany
| | - Daniel Stern
- Biological Toxins (ZBS 3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, 13353, Germany
| | - Diana Pauly
- Biological Toxins (ZBS 3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, 13353, Germany
- Department of Ophthalmology, University Hospital Regensburg, Regensburg, 93053, Germany
| | - Stefan Mahrhold
- Institut für Toxikologie, Medizinische Hochschule Hannover, 30625, Hannover, Germany
| | - Jasmin Weisemann
- Institut für Toxikologie, Medizinische Hochschule Hannover, 30625, Hannover, Germany
| | - Lisa Jentsch
- Biological Toxins (ZBS 3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, 13353, Germany
| | - Eva-Maria Hansbauer
- Biological Toxins (ZBS 3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, 13353, Germany
| | - Christian Müller
- Spiez Laboratory, Federal Office for Civil Protection, Spiez, 3700, Switzerland
| | - Marc A Avondet
- Spiez Laboratory, Federal Office for Civil Protection, Spiez, 3700, Switzerland
| | - Andreas Rummel
- Institut für Toxikologie, Medizinische Hochschule Hannover, 30625, Hannover, Germany
| | - Martin B Dorner
- Biological Toxins (ZBS 3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, 13353, Germany
| | - Brigitte G Dorner
- Biological Toxins (ZBS 3), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Berlin, 13353, Germany.
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Sarita R, Ponmariappan S, Sharma A, Kamboj DV, Jain AK. Development of immunodetection system for botulinum neurotoxin serotype E. Indian J Med Res 2018; 147:603-610. [PMID: 30168493 PMCID: PMC6118135 DOI: 10.4103/ijmr.ijmr_1375_16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Background & objectives Botulism, a potentially fatal paralytic illness, is caused by the botulinum neurotoxins (BoNTs) secreted by Clostridium botulinum. It is an obligate anaerobic, Gram-positive, spore-forming bacterium. BoNTs are classified into seven serotypes based on the serological properties. Among these seven serotypes, A, B, E and, rarely, F are responsible for human botulism. The present study was undertaken to develop an enzyme-linked immunosorbent assay (ELISA)-based detection system for the detection of BoNT/E. Methods The synthetic gene coding the light chain of BoNT serotype E (BoNT/E LC) was constructed using the polymerase chain reaction primer overlapping method, cloned into pQE30UA vector and then transformed into Escherichia coli M15 host cells. Recombinant protein expression was optimized using different concentrations of isopropyl-β-D-1-thiogalactopyranoside (IPTG), different temperature and the rBoNT/E LC protein was purified in native conditions using affinity column chromatography. The purified recombinant protein was checked by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and further confirmed by western blot and matrix-assisted laser desorption ionization-tandem time-of-flight (MALDI-TOF). Polyclonal antibodies were generated against rBoNT/E LC using Freund's adjuvant in BALB/c mice and rabbit. Sandwich ELISA was optimized for the detection of rBoNT/E LC and native crude BoNT/E, and food matrix interference was tested. The developed antibodies were further evaluated for their specificity/cross-reactivity with BoNT serotypes and other bacterial toxins. Results BoNT/E LC was successfully cloned, and the maximum expression was achieved in 16 h of post-induction using 0.5 mM IPTG concentration at 25°C. Polyclonal antibodies were generated in BALB/c mice and rabbit and the antibody titre was raised up to 128,000 after the 2nd booster dose. The developed polyclonal antibodies were highly specific and sensitive with a detection limit about 50 ng/ml for rBoNT/E LC and 2.5×10[3] MLD50 of native crude BoNT/E at a dilution of 1:3000 of mouse (capturing) and rabbit (revealing) antibodies. Further, different liquid, semisolid and solid food matrices were tested, and rBoNT/E LC was detected in almost all food samples, but different levels of interference were detected in different food matrices. Interpretation & conclusions There is no immune detection system available commercially in India to detect botulism. The developed system might be useful for the detection of botulinum toxin in food and clinical samples. Further work is in progress.
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Affiliation(s)
- R Sarita
- Biotechnology Division, Defence Research Development & Establishment, Gwalior, India
| | | | - Arti Sharma
- Biotechnology Division, Defence Research Development & Establishment, Gwalior, India
| | - Dev Vrat Kamboj
- Biotechnology Division, Defence Research Development & Establishment, Gwalior, India
| | - A K Jain
- School of Studies in Zoology, Jiwaji University, Gwalior, India
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Duracova M, Klimentova J, Fucikova A, Dresler J. Proteomic Methods of Detection and Quantification of Protein Toxins. Toxins (Basel) 2018; 10:toxins10030099. [PMID: 29495560 PMCID: PMC5869387 DOI: 10.3390/toxins10030099] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 02/21/2018] [Accepted: 02/23/2018] [Indexed: 12/11/2022] Open
Abstract
Biological toxins are a heterogeneous group of compounds that share commonalities with biological and chemical agents. Among them, protein toxins represent a considerable, diverse set. They cover a broad range of molecular weights from less than 1000 Da to more than 150 kDa. This review aims to compare conventional detection methods of protein toxins such as in vitro bioassays with proteomic methods, including immunoassays and mass spectrometry-based techniques and their combination. Special emphasis is given to toxins falling into a group of selected agents, according to the Centers for Disease Control and Prevention, such as Staphylococcal enterotoxins, Bacillus anthracis toxins, Clostridium botulinum toxins, Clostridium perfringens epsilon toxin, ricin from Ricinus communis, Abrin from Abrus precatorius or control of trade in dual-use items in the European Union, including lesser known protein toxins such as Viscumin from Viscum album. The analysis of protein toxins and monitoring for biological threats, i.e., the deliberate spread of infectious microorganisms or toxins through water, food, or the air, requires rapid and reliable methods for the early identification of these agents.
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Affiliation(s)
- Miloslava Duracova
- Faculty of Military Health Sciences, University of Defense in Brno, Třebešská 1575, CZ-500 01 Hradec Králové, Czech Republic.
| | - Jana Klimentova
- Faculty of Military Health Sciences, University of Defense in Brno, Třebešská 1575, CZ-500 01 Hradec Králové, Czech Republic.
| | - Alena Fucikova
- Faculty of Military Health Sciences, University of Defense in Brno, Třebešská 1575, CZ-500 01 Hradec Králové, Czech Republic.
| | - Jiri Dresler
- Military Health Institute, Military Medical Agency, Tychonova 1, CZ-160 00 Prague 6, Czech Republic.
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A Novel Surface Plasmon Resonance Biosensor for the Rapid Detection of Botulinum Neurotoxins. BIOSENSORS-BASEL 2017; 7:bios7030032. [PMID: 28783115 PMCID: PMC5618038 DOI: 10.3390/bios7030032] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 07/28/2017] [Accepted: 08/01/2017] [Indexed: 11/16/2022]
Abstract
Botulinum neurotoxins (BoNTs) are Category A agents on the NIAID (National Institute of Allergy and Infectious Diseases) priority pathogen list owing to their extreme toxicity and the relative ease of production. These deadly toxins, in minute quantities (estimated human i.v. lethal dose LD50 of 1-2 ng/kg body weight), cause fatal flaccid paralysis by blocking neurotransmitter release. The current gold standard detection method, the mouse-bioassay, often takes days to confirm botulism. Furthermore, there are no effective antidotes known to reverse the symptoms of botulism, and as a result, patients with severe botulism often require meticulous care during the prolonged paralytic illness. To combat potential bio-terrorism incidents of botulinum neurotoxins, their rapid detection is paramount. Surface plasmon resonance (SPR) is a very sensitive technique to examine bio-molecular interactions. The label-free, real-time analysis, with high sensitivity and low sample consumption makes this technology particularly suitable for detection of the toxin. In this study, we demonstrated the feasibility in an assay with a newly designed SPR instrument for the rapid detection of botulinum neurotoxins. The LOD (limit of detection) of the Newton Photonics (NP) SPR based assay is 6.76 pg/mL for Botulinum Neurotoxin type A Light Chain (BoNT/A LC). We established that the detection sensitivity of the system is comparable to the traditional mouse LD50 bioassay in BoNT/A using this SPR technology.
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Development of an Innovative in Vitro Potency Assay for Anti-Botulinum Antitoxins. Toxins (Basel) 2016; 8:toxins8100276. [PMID: 27669303 PMCID: PMC5086636 DOI: 10.3390/toxins8100276] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 09/14/2016] [Accepted: 09/19/2016] [Indexed: 11/17/2022] Open
Abstract
Botulinum neurotoxins are bacterial proteins that cause botulism, a life-threatening disease. Therapy relies mostly on post-intoxication antibody treatment. The only accepted method to measure the potency of, and to approve, antitoxin preparations is the mouse lethality neutralization bioassay. However, this assay is time-consuming, labor-intensive, costly, and raises ethical issues related to the large numbers of laboratory animals needed. Until now, all efforts to develop an alternative in vitro assay have not provided a valid replacement to the mouse potency assay. In the present study, we report the development of an innovative in vitro assay for determining botulinum antitoxin potency, using botulinum type B as a model. The concept of the assay is to mimic two fundamental steps in botulinum intoxication: receptor binding and catalytic activity. By simulating these steps in vitro we were able to accurately determine the potency of antitoxin preparations. The reproducibility of the assay was high with a CV < 13%. Most importantly, the antitoxin potency measured by the in vitro assay highly correlated with that measured by the standard in vivo mouse assay (r = 0.9842, p < 0.0001). Thus, this new in vitro assay has the potential to be considered, after validation, as a replacement to the mouse assay for quantitating neutralizing antibody concentrations in pharmaceutical botulinum antitoxin preparations. Future adoption of this in vitro assay would minimize the use of laboratory animals, speed up the time, and reduce the cost of botulinum antitoxin approval.
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Worbs S, Fiebig U, Zeleny R, Schimmel H, Rummel A, Luginbühl W, Dorner BG. Qualitative and Quantitative Detection of Botulinum Neurotoxins from Complex Matrices: Results of the First International Proficiency Test. Toxins (Basel) 2015; 7:4935-66. [PMID: 26703724 PMCID: PMC4690107 DOI: 10.3390/toxins7124857] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 11/03/2015] [Accepted: 11/05/2015] [Indexed: 11/16/2022] Open
Abstract
In the framework of the EU project EQuATox, a first international proficiency test (PT) on the detection and quantification of botulinum neurotoxins (BoNT) was conducted. Sample materials included BoNT serotypes A, B and E spiked into buffer, milk, meat extract and serum. Different methods were applied by the participants combining different principles of detection, identification and quantification. Based on qualitative assays, 95% of all results reported were correct. Successful strategies for BoNT detection were based on a combination of complementary immunological, MS-based and functional methods or on suitable functional in vivo/in vitro approaches (mouse bioassay, hemidiaphragm assay and Endopep-MS assay). Quantification of BoNT/A, BoNT/B and BoNT/E was performed by 48% of participating laboratories. It turned out that precise quantification of BoNT was difficult, resulting in a substantial scatter of quantitative data. This was especially true for results obtained by the mouse bioassay which is currently considered as "gold standard" for BoNT detection. The results clearly demonstrate the urgent need for certified BoNT reference materials and the development of methods replacing animal testing. In this context, the BoNT PT provided the valuable information that both the Endopep-MS assay and the hemidiaphragm assay delivered quantitative results superior to the mouse bioassay.
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Affiliation(s)
- Sylvia Worbs
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestrasse 10, 13353 Berlin, Germany.
| | - Uwe Fiebig
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestrasse 10, 13353 Berlin, Germany.
| | - Reinhard Zeleny
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg 111, 2440 Geel, Belgium.
| | - Heinz Schimmel
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg 111, 2440 Geel, Belgium.
| | - Andreas Rummel
- toxogen GmbH, Feodor-Lynen-Strasse 35, 30625 Hannover, Germany.
| | | | - Brigitte G Dorner
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestrasse 10, 13353 Berlin, Germany.
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Rosen O, Feldberg L, Gura S, Zichel R. A new peptide substrate for enhanced botulinum neurotoxin type B detection by endopeptidase–liquid chromatography–tandem mass spectrometry/multiple reaction monitoring assay. Anal Biochem 2015; 473:7-10. [DOI: 10.1016/j.ab.2014.09.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 09/21/2014] [Accepted: 09/22/2014] [Indexed: 10/24/2022]
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Wang D, Baudys J, Krilich J, Smith TJ, Barr JR, Kalb SR. A two-stage multiplex method for quantitative analysis of botulinum neurotoxins type A, B, E, and F by MALDI-TOF mass spectrometry. Anal Chem 2014; 86:10847-54. [PMID: 25285509 DOI: 10.1021/ac502948v] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In this publication, we report on the development of a quantitative enzymatic method for the detection of four botulinum neurotoxin (BoNT) serotypes responsible for human botulism by MALDI-TOF mass spectrometry. Factors that might affect the linearity and dynamic range for detection of BoNT cleavage products were initially examined, including the amount of peptide substrate and internal standard, the timing of cleavage reaction, and the components in the reaction solution. It was found that a long incubation time produced sensitive results, but was not capable of determining higher toxin concentrations, whereas a short incubation time was less sensitive so that lower toxin concentrations were not detected. In order to overcome these limitations, a two-stage analysis strategy was applied. The first stage analysis involved a short incubation period (e.g., 30 min). If no toxin was detected at this stage, the cleavage reaction was allowed to continue and the samples were analyzed at a second time point (4 h), so that toxin levels lower than 1 mouse LD50 or 55 attomoles per milliliter (55 amol/mL) could be quantified. By combining the results from two-stage quantification, 4 or 5 orders of magnitude in dynamic range were achieved for the detection of the serotypes of BoNT/A, BoNT/B, BoNT/E, or BoNT/F. The effect of multiplexing the assay by mixing substrates for different BoNT serotypes into a single reaction was also investigated in order to reduce the numbers of the cleavage reactions and save valuable clinical samples.
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Affiliation(s)
- Dongxia Wang
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention , Atlanta, Georgia 30341, United States
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Schibel AE, Ervin EN. Antigen detection via the rate of ion current rectification change of the antibody-modified glass nanopore membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:11248-11256. [PMID: 25157668 PMCID: PMC4172300 DOI: 10.1021/la502714b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 08/21/2014] [Indexed: 06/03/2023]
Abstract
Ion current rectification (ICR), defined as an increase in ion conduction at a given polarity and a decrease in ion conduction for the same voltage at the opposite polarity, i.e., a deviation from a linear ohmic response, occurs in conical shaped pores due to the voltage dependent solution conductivity within the aperture. The degree to which the ionic current rectifies is a function of the size and surface charge of the nanopore, with smaller and more highly charged pores exhibiting greater degrees of rectification. The ICR phenomenon has previously been exploited for biosensing applications, where the level of ICR for a nanopore functionalized with an analyte-specific binding molecule (e.g., an antibody, biotin, etc.) changes upon binding its target analyte (e.g., an antigen, streptavidin, etc.) due to a resulting change in the size and/or charge of the aperture. While this type of detection measurement is typically qualitative, for the first time, we demonstrate that the rate at which the nanopore ICR response changes is dependent on the concentration of the target analyte introduced. Utilizing a glass nanopore membrane (GNM) internally coated with a monoclonal antibody specific to the cleaved form of synaptosomal-associated protein 25 (cSNAP-25), creating the antibody-modified glass nanopore membrane (AMGNM), we demonstrate a correlation between the rate of ICR change and the concentration of introduced cSNAP-25, over a range of 500 nM-100 μM. The methodology presented here significantly expands the applications of nanopore ICR biosensing measurements and demonstrates that these measurements can be quantitative in nature.
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Björnstad K, Tevell Åberg A, Kalb SR, Wang D, Barr JR, Bondesson U, Hedeland M. Validation of the Endopep-MS method for qualitative detection of active botulinum neurotoxins in human and chicken serum. Anal Bioanal Chem 2014; 406:7149-61. [PMID: 25228079 DOI: 10.1007/s00216-014-8170-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 09/04/2014] [Accepted: 09/05/2014] [Indexed: 11/28/2022]
Abstract
Botulinum neurotoxins (BoNTs) are highly toxic proteases produced by anaerobic bacteria. Traditionally, a mouse bioassay (MBA) has been used for detection of BoNTs, but for a long time, laboratories have worked with alternative methods for their detection. One of the most promising in vitro methods is a combination of an enzymatic and mass spectrometric assay called Endopep-MS. However, no comprehensive validation of the method has been presented. The main purpose of this work was to perform a validation for the qualitative analysis of BoNT-A, B, C, C/D, D, D/C, and F in serum. The limit of detection (LOD), selectivity, precision, stability in matrix and solution, and correlation with the MBA were evaluated. The LOD was equal to or even better than that of the MBA for BoNT-A, B, D/C, E, and F. Furthermore, Endopep-MS was for the first time successfully used to differentiate between BoNT-C and D and their mosaics C/D and D/C by different combinations of antibodies and target peptides. In addition, sequential antibody capture was presented as a new way to multiplex the method when only a small sample volume is available. In the comparison with the MBA, all the samples analyzed were positive for BoNT-C/D with both methods. These results indicate that the Endopep-MS method is a valid alternative to the MBA as the gold standard for BoNT detection based on its sensitivity, selectivity, and speed and that it does not require experimental animals.
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Affiliation(s)
- Kristian Björnstad
- Department of Chemistry, Environment and Feed Hygiene, National Veterinary Institute (SVA), 751 89, Uppsala, Sweden
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Torii Y, Goto Y, Nakahira S, Ginnaga A. Establishment of alternative potency test for botulinum toxin type A using compound muscle action potential (CMAP) in rats. Toxicon 2014; 90:97-105. [PMID: 25110177 DOI: 10.1016/j.toxicon.2014.07.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 06/24/2014] [Accepted: 07/24/2014] [Indexed: 12/27/2022]
Abstract
The biological activity of botulinum toxin type A has been evaluated using the mouse intraperitoneal (ip) LD50 test. This method requires a large number of mice to precisely determine toxin activity, and, as such, poses problems with regard to animal welfare. We previously developed a compound muscle action potential (CMAP) assay using rats as an alternative method to the mouse ip LD50 test. In this study, to evaluate this quantitative method of measuring toxin activity using CMAP, we assessed the parameters necessary for quantitative tests according to ICH Q2 (R1). This assay could be used to evaluate the activity of the toxin, even when inactive toxin was mixed with the sample. To reduce the number of animals needed, this assay was set to measure two samples per animal. Linearity was detected over a range of 0.1-12.8 U/mL, and the measurement range was set at 0.4-6.4 U/mL. The results for accuracy and precision showed low variability. The body weight was selected as a variable factor, but it showed no effect on the CMAP amplitude. In this study, potency tests using the rat CMAP assay of botulinum toxin type A demonstrated that it met the criteria for a quantitative analysis method.
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Affiliation(s)
- Yasushi Torii
- The Chemo-Sero- Therapeutic Research Institute (KAKETSUKEN), 1-6-1 Okubo, Kita-ku, Kumamoto-shi, Kumamoto 860-8568, Japan; Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita-shi, Osaka 565-0871, Japan.
| | - Yoshitaka Goto
- The Chemo-Sero- Therapeutic Research Institute (KAKETSUKEN), 1-6-1 Okubo, Kita-ku, Kumamoto-shi, Kumamoto 860-8568, Japan
| | - Shinji Nakahira
- The Chemo-Sero- Therapeutic Research Institute (KAKETSUKEN), 1-6-1 Okubo, Kita-ku, Kumamoto-shi, Kumamoto 860-8568, Japan
| | - Akihiro Ginnaga
- The Chemo-Sero- Therapeutic Research Institute (KAKETSUKEN), 1-6-1 Okubo, Kita-ku, Kumamoto-shi, Kumamoto 860-8568, Japan
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Koizumi H, Goto S, Okita S, Morigaki R, Akaike N, Torii Y, Harakawa T, Ginnaga A, Kaji R. Spinal Central Effects of Peripherally Applied Botulinum Neurotoxin A in Comparison between Its Subtypes A1 and A2. Front Neurol 2014; 5:98. [PMID: 25002857 PMCID: PMC4066301 DOI: 10.3389/fneur.2014.00098] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 05/31/2014] [Indexed: 01/28/2023] Open
Abstract
Because of its unique ability to exert long-lasting synaptic transmission blockade, botulinum neurotoxin A (BoNT/A) is used to treat a wide variety of disorders involving peripheral nerve terminal hyperexcitability. However, it has been a matter of debate whether this toxin has central or peripheral sites of action. We employed a rat model in which BoNT/A1 or BoNT/A2 was unilaterally injected into the gastrocnemius muscle. On time-course measurements of compound muscle action potential (CMAP) amplitudes after injection of BoNT/A1 or BoNT/A2 at doses ranging from 1.7 to 13.6 U, CMAP amplitude for the ipsilateral hind leg was markedly decreased on the first day, and this muscle flaccidity persisted up to the 14th day. Of note, both BoNT/A1 and BoNT/A2 administrations also resulted in decreased CMAP amplitudes for the contralateral leg in a dose-dependent manner ranging from 1.7 to 13.6 U, and this muscle flaccidity increased until the fourth day and then slowly recovered. Immunohistochemical results revealed that BoNT/A-cleaved synaptosomal-associated protein of 25 kDa (SNAP-25) appeared in the bilateral ventral and dorsal horns 4 days after injection of BoNT/A1 (10 U) or BoNT/A2 (10 U), although there seemed to be a wider spread of BoNT/A-cleaved SNAP-25 associated with BoNT/A1 than BoNT/A2 in the contralateral spinal cord. This suggests that the catalytically active BoNT/A1 and BoNT/A2 were axonally transported via peripheral motor and sensory nerves to the spinal cord, where they spread through a transcytosis (cell-to-cell trafficking) mechanism. Our results provide evidence for the central effects of intramuscularly administered BoNT/A1 and BoNT/A2 in the spinal cord, and a new insight into the clinical effects of peripheral BoNT/A applications.
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Affiliation(s)
- Hidetaka Koizumi
- Department of Clinical Neuroscience, Institute of Health Biosciences, Graduate School of Medical Sciences, University of Tokushima , Tokushima , Japan ; Department of Motor Neuroscience and Neurotherapeutics, Institute of Health Biosciences, Graduate School of Medical Sciences, University of Tokushima , Tokushima , Japan
| | - Satoshi Goto
- Department of Motor Neuroscience and Neurotherapeutics, Institute of Health Biosciences, Graduate School of Medical Sciences, University of Tokushima , Tokushima , Japan
| | - Shinya Okita
- Department of Motor Neuroscience and Neurotherapeutics, Institute of Health Biosciences, Graduate School of Medical Sciences, University of Tokushima , Tokushima , Japan
| | - Ryoma Morigaki
- Department of Motor Neuroscience and Neurotherapeutics, Institute of Health Biosciences, Graduate School of Medical Sciences, University of Tokushima , Tokushima , Japan
| | - Norio Akaike
- Research Division for Life Science, Kumamoto Health Science University , Kumamoto , Japan
| | - Yasushi Torii
- The Chemo-Sero-Therapeutic Research Institute (KAKETSUKEN) , Kumamoto , Japan ; Graduate School of Medicine, Osaka University , Osaka , Japan
| | - Tetsuhiro Harakawa
- The Chemo-Sero-Therapeutic Research Institute (KAKETSUKEN) , Kumamoto , Japan
| | - Akihiro Ginnaga
- The Chemo-Sero-Therapeutic Research Institute (KAKETSUKEN) , Kumamoto , Japan
| | - Ryuji Kaji
- Department of Clinical Neuroscience, Institute of Health Biosciences, Graduate School of Medical Sciences, University of Tokushima , Tokushima , Japan
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Abstract
The aim of this work was to present selected data regarding traditional and modern methods for C. botulinum and its toxins detection. In this article, methods based on culturing techniques, mouse bioassay, immunological techniques, chromatography and PCR, PFGE, RFLP, AFLP are described. The mentioned techniques were evaluated considering their usefulness in the samples examination, genotyping of strains and the diagnostics of botulism.
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Rosen O, Feldberg L, Gura S, Zichel R. Improved detection of botulinum type E by rational design of a new peptide substrate for endopeptidase-mass spectrometry assay. Anal Biochem 2014; 456:50-2. [PMID: 24721293 DOI: 10.1016/j.ab.2014.03.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 03/26/2014] [Accepted: 03/29/2014] [Indexed: 12/01/2022]
Abstract
Botulinum neurotoxins (BoNTs) are the most toxic substances known to humans. Endopeptidase-mass spectrometry (Endopep-MS) is used as a specific and rapid in vitro assay to detect BoNTs. In this assay, immunocaptured toxin cleaves a serotype-specific peptide substrate, and the cleavage products are then detected by MS. To further improve the sensitivity of the assay, we report here the rational design of a new substrate peptide for the detection of botulinum neurotoxin type E (BoNT/E). Our strategy was based on previously reported structural interactions integrated with analysis method efficiency considerations. Integration of the newly designed substrate has led to a more than one order of magnitude increased sensitivity of the assay.
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Affiliation(s)
- Osnat Rosen
- Department of Biotechnology, Israel Institute for Biological Research, Ness Ziona 7410001, Israel
| | - Liron Feldberg
- Department of Analytical Chemistry, Israel Institute for Biological Research, Ness Ziona 7410001, Israel
| | - Sigalit Gura
- Department of Analytical Chemistry, Israel Institute for Biological Research, Ness Ziona 7410001, Israel
| | - Ran Zichel
- Department of Biotechnology, Israel Institute for Biological Research, Ness Ziona 7410001, Israel.
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Tevell Åberg A, Björnstad K, Hedeland M. Mass Spectrometric Detection of Protein-Based Toxins. Biosecur Bioterror 2013; 11 Suppl 1:S215-26. [DOI: 10.1089/bsp.2012.0072] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Annica Tevell Åberg
- Annica Tevell Åberg, PhD, is a Senior Researcher; Kristian Björnstad, PhD, is a Senior Researcher; and Mikael Hedeland, PhD, is an Associate Professor and Deputy Head of Department; all at the Department of Chemistry, Environment and Feed Hygiene, National Veterinary Institute (SVA), Uppsala, Sweden. Dr. Åberg and Dr. Hedeland are also affiliated with the Division of Analytical Pharmaceutical Chemistry, Uppsala University, Uppsala, Sweden
| | - Kristian Björnstad
- Annica Tevell Åberg, PhD, is a Senior Researcher; Kristian Björnstad, PhD, is a Senior Researcher; and Mikael Hedeland, PhD, is an Associate Professor and Deputy Head of Department; all at the Department of Chemistry, Environment and Feed Hygiene, National Veterinary Institute (SVA), Uppsala, Sweden. Dr. Åberg and Dr. Hedeland are also affiliated with the Division of Analytical Pharmaceutical Chemistry, Uppsala University, Uppsala, Sweden
| | - Mikael Hedeland
- Annica Tevell Åberg, PhD, is a Senior Researcher; Kristian Björnstad, PhD, is a Senior Researcher; and Mikael Hedeland, PhD, is an Associate Professor and Deputy Head of Department; all at the Department of Chemistry, Environment and Feed Hygiene, National Veterinary Institute (SVA), Uppsala, Sweden. Dr. Åberg and Dr. Hedeland are also affiliated with the Division of Analytical Pharmaceutical Chemistry, Uppsala University, Uppsala, Sweden
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21
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Jones RGA, Marks JD. Use of a new functional dual coating (FDC) assay to measure low toxin levels in serum and food samples following an outbreak of human botulism. J Med Microbiol 2013; 62:828-835. [DOI: 10.1099/jmm.0.053124-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Clostridium
botulinum type A toxin is the most prevalent cause of naturally occurring outbreaks of human botulism in the world. The active dichain neurotoxin molecule is composed of a heavy chain (H-chain) of ~100 kDa with the carboxy-terminal end consisting of a receptor-binding (HC) domain, while the amino-terminal (HN) domain is linked by a critical disulfide bond to a light chain (L-chain) of ~50 kDa. Although the mouse bioassay (MBA) is traditionally used to confirm the presence of toxin in serum or food, its sensitivity is insufficient to detect low toxin levels in approximately 30 to 60 % of botulism patients. A novel FDC (functional dual coating) microtitre plate immuno-biochemical assay, which quantifies botulinum toxicity by measuring the HC domain linked with L-chain endopeptidase activity, was modified to allow human serum (lysed or unlysed) to be tested without interference from the matrix, with toxin detection down to 0.03 mouse LD50 per ml serum or 0.13 pg ml–1 using just 100 µl of clinical samples. The assay was specific for type A toxin and could additionally be applied to whole blood and food samples. Low levels of 1 to 2 mouse LD50 per ml serum of type A toxin were quantified for the first time using the modified FDC assay in two severely intoxicated UK patients who required mechanical ventilation and antitoxin. Toxin levels in recovered food sample extracts were also detected and one MBA-negative sample was found to contain 0.32 LD50 per ml extract. The FDC assay provides a real alternative for public health laboratories to unambiguously confirm all cases of type A botulism and, due to its sensitivity, a promising new tool in toxin pharmacokinetic studies.
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Affiliation(s)
- Russell G. A. Jones
- Division of Bacteriology, National Institute for Biological Standards and Control, Health Protection Agency, South Mimms, Hertfordshire, UK
| | - James D. Marks
- Department of Anesthesia, University of California, San Francisco, USA
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22
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Hypersensitive detection and quantitation of BoNT/A by IgY antibody against substrate linear-peptide. PLoS One 2013; 8:e58908. [PMID: 23555605 PMCID: PMC3605418 DOI: 10.1371/journal.pone.0058908] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 02/08/2013] [Indexed: 11/19/2022] Open
Abstract
Botulinum neurotoxin A (BoNT/A), the most acutely poisonous substance to humans known, cleave its SNAP-25 substrate with high specificity. Based on the endopeptidase activity, different methods have been developed to detect BoNT/A, but most lack ideal reproducibility or sensitivity, or suffer from long-term or unwanted interferences. In this study, we developed a simple method to detect and quantitate trace amounts of botulinum neurotoxin A using the IgY antibody against a linear-peptide substrate. The effects of reaction buffer, time, and temperature were analyzed and optimized. When the optimized assay was used to detect BoNT/A, the limit of detection of the assay was 0.01 mouse LD50 (0.04 pg), and the limit of quantitation was 0.12 mouse LD50/ml (0.48 pg). The findings also showed favorable specificity of detecting BoNT/A. When used to detect BoNT/A in milk or human serum, the proposed assay exhibited good quantitative accuracy (88% < recovery < 111%; inter- and intra-assay CVs < 18%). This method of detection took less than 3 h to complete, indicating that it can be a valuable method of detecting BoNT/A in food or clinical diagnosis.
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Dadgar S, Ramjan Z, Floriano WB. Paclitaxel is an inhibitor and its boron dipyrromethene derivative is a fluorescent recognition agent for botulinum neurotoxin subtype A. J Med Chem 2013; 56:2791-803. [PMID: 23484537 DOI: 10.1021/jm301829h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We have successfully identified one new inhibitor and one new fluorescent recognition agent for the botulinum neurotoxin subtype A (BoNT/A) using the virtual screening protocol "protein scanning with virtual ligand screening" (PSVLS). Hit selection used an in-house developed holistic binding scoring method. Selected hits were tested experimentally for inhibitory activity using fluorescence resonance energy transfer (FRET) assays against the light chain (catalytic domain) of BoNT/A. Ligand binding was determined against the light and heavy chain BoNT/A complex through either radiolabeled ligand binding assays (nonfluorescent ligands) or fluorescence intensity assays (fluorescent ligands). These experimental assays have confirmed one compound (paclitaxel) to inhibit BoNT/A's proteolytic activity experimentally with an IC50 of 5.2 μM. A fluorescent derivative was also confirmed to bind to the toxin and therefore is a suitable candidate for the rational design of new detection agents and for the development of fluorescence-based multiprobe detection assays.
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Affiliation(s)
- Saedeh Dadgar
- Department of Chemistry, Lakehead University and Thunder Bay Regional Research Institute, Thunder Bay, Ontario P7B 5E1, Canada
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Kim CS, Jang W, Son I, Nam S, Kim Y, Park K, Kim B, Kim M. Electrophysiological study for comparing the effect of biological activity between type A botulinum toxins in rat gastrocnemius muscle. Hum Exp Toxicol 2013; 32:914-20. [DOI: 10.1177/0960327113479044] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background: New cosmetic applications and products based on the effects of botulinum toxin (BTX) treatment have stimulated demand for this class of natural compounds. This demand generates the need for appropriate standardized protocols to test and compare the effectiveness of new BTX preparations. Objectives: Based on the previously described electrophysiological methods, we measured and compared the inhibitory effects of two BTX type A (BTX-A) preparations on neuromuscular transmission through split-body test. Methods: The effectiveness was evaluated in terms of the compound muscle action potential (CMAP) and conduction velocity after BTX-A injection. We used a split-body method to compare two different BTX-As in the rat. Results: Based on the changes in the CMAP, the two different BTX-As induced paralytic effect on the rat tibialis anterior muscle. However, the two different BTX-A preparations did not differ significantly in effectiveness and did not induce a delay in conduction velocity. Conclusions: The new BTX-A preparation used in this electrophysiological study had similar effect compared with the previously marketed BTX-A.[AQ: Please approve the edits made to the sentence “The new BTX-A preparation…”) We propose that a split-body electrophysiological protocol will be useful in establishing the comparative effectiveness of new BTX products.
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Affiliation(s)
- C-S. Kim
- Daewoong Pharmaceutical Co., Ltd, Seoul, Republic of Korea
| | - W.S. Jang
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - I.P. Son
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - S.H. Nam
- Daewoong Pharmaceutical Co., Ltd, Seoul, Republic of Korea
| | - Y.I. Kim
- Daewoong Pharmaceutical Co., Ltd, Seoul, Republic of Korea
| | - K.Y. Park
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - B.J. Kim
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - M.N. Kim
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Republic of Korea
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Development of a Cell-Based Functional Assay for the Detection of Clostridium botulinum Neurotoxin Types A and E. Int J Microbiol 2013; 2013:593219. [PMID: 23533420 PMCID: PMC3606727 DOI: 10.1155/2013/593219] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 01/22/2013] [Accepted: 01/30/2013] [Indexed: 11/17/2022] Open
Abstract
The standard procedure for definitive detection of BoNT-producing Clostridia is a culture method combined with neurotoxin detection using a standard mouse bioassay (MBA). The mouse bioassay is highly sensitive and specific, but it is expensive and time-consuming, and there are ethical concerns due to use of laboratory animals. Cell-based assays provide an alternative to the MBA in screening for BoNT-producing Clostridia. Here, we describe a cell-based assay utilizing a fluorescence reporter construct expressed in a neuronal cell model to study toxin activity in situ. Our data indicates that the assay can detect as little as 100 pM BoNT/A activity within living cells, and the assay is currently being evaluated for the analysis of BoNT in food matrices. Among available in vitro assays, we believe that cell-based assays are widely applicable in high-throughput screenings and have the potential to at least reduce and refine animal assays if not replace it.
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Ouimet T, Duquesnoy S, Poras H, Fournié-Zaluski MC, Roques BP. Comparison of Fluorigenic Peptide Substrates PL50, SNAPtide, and BoTest A/E for BoNT/A Detection and Quantification. ACTA ACUST UNITED AC 2013; 18:726-35. [DOI: 10.1177/1087057113476089] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Detection and quantification of low doses of botulinum toxin serotype A (BoNT/A) in medicinal preparations require precise and sensitive methods. With mounting pressure from governmental authorities to replace the mouse LD50 assay, interest in alternative methods such as the endopeptidase assay, quantifying the toxin active moiety, is growing. Using internal collision-induced fluorescence quenching, Pharmaleads produced peptides encompassing the SNAP-25 cleavage site: a 17-mer (PL63) and a 48-mer (PL50) reaching the previously identified α-exosite, with PL50 showing higher apparent affinity for BoNT/A. Peptide mapping experiments revealed that this increased affinity is mainly due to a connecting peptide sequence between the N-terminus of PL63 and the α-exosite, identifying a new cooperative exosite on BoNT/A. Other endopeptidase substrates available, including SNAPTide and BoTest A/E, are both based on fluorescent resonance energy transfer (FRET) technology. To compare these assays, their limits of detection and quantification were determined using light chain or 150-kDa BoNT/A. Detection limits of PL50 and BoTest were over 100 times better than those using SNAPtide in standard conditions. Although the BoTest possessed a detection limit around 0.2 pM for either BoNT/A form, its quantification limit (9.7 pM) using purified BoNT/A was 12 times inferior to PL50, estimated at 0.8 pM, suitable for medicinal preparation quantification.
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Chung ME, Song DH, Park JH. Comparative Study of Biological Activity of Four Botulinum Toxin Type A Preparations in Mice. Dermatol Surg 2013; 39:155-64. [DOI: 10.1111/dsu.12071] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kim SH, Kim SB, Yang GH, Rhee CH. Mouse compound muscle action potential assay: An alternative method to conduct the LD50 botulinum toxin type A potency test. Toxicon 2012; 60:341-7. [DOI: 10.1016/j.toxicon.2012.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 05/03/2012] [Accepted: 05/08/2012] [Indexed: 12/01/2022]
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29
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Liu YY, Rigsby P, Sesardic D, Marks JD, Jones RG. A functional dual-coated (FDC) microtiter plate method to replace the botulinum toxin LD50 test. Anal Biochem 2012; 425:28-35. [DOI: 10.1016/j.ab.2012.02.038] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 02/24/2012] [Accepted: 02/28/2012] [Indexed: 11/17/2022]
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Joshi SG. Detection of biologically active botulinum neurotoxin-A in serum using high-throughput FRET-assay. J Pharmacol Toxicol Methods 2012; 65:8-12. [PMID: 22178409 DOI: 10.1016/j.vascn.2011.11.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 11/16/2011] [Accepted: 11/25/2011] [Indexed: 10/14/2022]
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Dorner MB, Schulz KM, Kull S, Dorner BG. Complexity of Botulinum Neurotoxins: Challenges for Detection Technology. Curr Top Microbiol Immunol 2012. [DOI: 10.1007/978-3-662-45790-0_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Detection, Differentiation and Subtyping of Botulinum Neurotoxins in Clinical Samples with Mass Spectrometry. ACTA ACUST UNITED AC 2011. [DOI: 10.1021/bk-2011-1065.ch006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Depolarization after resonance energy transfer (DARET): A sensitive fluorescence-based assay for botulinum neurotoxin protease activity. Anal Biochem 2011; 413:36-42. [DOI: 10.1016/j.ab.2011.01.043] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/28/2011] [Accepted: 01/29/2011] [Indexed: 01/03/2023]
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Gray SA, Barr JR, Kalb SR, Marks JD, Baird CL, Cangelosi GA, Miller KD, Feldhaus MJ. Synergistic capture of Clostridium botulinum type A neurotoxin by scFv antibodies to novel epitopes. Biotechnol Bioeng 2011; 108:2456-67. [PMID: 21538339 DOI: 10.1002/bit.23196] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 04/19/2011] [Accepted: 04/22/2011] [Indexed: 11/07/2022]
Abstract
A non-immune library of human single chain fragment variable (scFv) antibodies displayed on Saccharomyces cerevisiae was screened for binding to the Clostridium botulinum neurotoxin serotype A binding domain [BoNT/A (Hc)] with the goal of identifying scFv to novel epitopes. To do this, an antibody-mediated labeling strategy was used in which antigen-binding yeast clones were selected after labeling with previously characterized monoclonal antibodies (MAbs) specific to the Hc. Twenty unique scFv clones were isolated that bound Hc. Of these, 3 also bound to full-length BoNT/A toxin complex with affinities ranging from 5 to 48 nM. Epitope binning showed that the three unique clones recognized at least two epitopes distinct from one another as well as from the detection MAbs. After production in E. coli, scFv were coupled to magnetic particles and tested for their ability to capture BoNT/A holotoxin using an Endopep-MS assay. In this assay, toxin captured by scFv coated magnetic particles was detected by incubation of the complex with a peptide containing a BoNT/A-specific cleavage sequence. Mass spectrometry was used to detect the ratio of intact peptide to cleavage products as evidence for toxin capture. When tested individually, each of the scFv showed a weak positive Endopep-MS result. However, when the particles were coated with all three scFv simultaneously, they exhibited significantly higher Endopep-MS activity, consistent with synergistic binding. These results demonstrate novel approaches toward the isolation and characterization of scFv antibodies specific to unlabeled antigens. They also provide evidence that distinct scFv antibodies can work synergistically to increase the efficiency of antigen capture onto a solid support.
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Affiliation(s)
- Sean A Gray
- Seattle Biomedical Research Institute, 307 Westlake Ave. N., Suite 500, Seattle, Washington 98109; telephone: 206-256-7143; fax: 206-256-7229.
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Hedeland M, Moura H, Båverud V, Woolfitt AR, Bondesson U, Barr JR. Confirmation of botulism in birds and cattle by the mouse bioassay and Endopep-MS. J Med Microbiol 2011; 60:1299-1305. [PMID: 21566090 DOI: 10.1099/jmm.0.031179-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
There have been several outbreaks of botulism among poultry and wild birds in Sweden in recent years. The National Veterinary Institute of Sweden (SVA) has identified botulinum neurotoxin (BoNT)/C1 or the mosaic BoNT/C1D using the mouse bioassay. This is believed to be the first report on the application of the Endopep mass spectrometry (Endopep-MS) method to selected clinical animal (serum and liver) samples and a feed sample that had previously given positive test results with the mouse bioassay. In the mouse bioassay eight of the eleven samples were found to be neutralized by both BoNT/C1 and /D antitoxins; the other three were neutralized only by BoNT/C1 antitoxin, but the mice showed a prolonged survival time when the samples had been treated with /D antitoxin. The Endopep-MS analysis, on the other hand, demonstrated only BoNT/C1 activity for all eleven samples. This suggests that at least eight of the samples were of the chimeric toxin type BoNT/C1D, where the enzymically active site is identical to that of BoNT/C1, while other parts of the protein contain sequences of BoNT/D. This is the first step of a cross-validation between the established mouse bioassay and the Endopep-MS of serotypes BoNT/C1 and /C1D. Endopep-MS is concluded to have potential as an attractive alternative to the mouse bioassay.
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Affiliation(s)
- Mikael Hedeland
- Uppsala University, Division of Analytical Pharmaceutical Chemistry, Biomedical Centre, PO Box 574, SE-751 23 Uppsala, Sweden.,National Veterinary Institute (SVA), Department of Chemistry, Environment and Feed Hygiene, SE-751 89 Uppsala, Sweden
| | - Hercules Moura
- Centers for Disease Control and Prevention, NCEH/DLS, 4770 Buford Hwy NE, Atlanta, GA 30341-3724, USA
| | - Viveca Båverud
- National Veterinary Institute (SVA), Department of Bacteriology, SE-751 89 Uppsala, Sweden
| | - Adrian R Woolfitt
- Centers for Disease Control and Prevention, NCEH/DLS, 4770 Buford Hwy NE, Atlanta, GA 30341-3724, USA
| | - Ulf Bondesson
- Uppsala University, Division of Analytical Pharmaceutical Chemistry, Biomedical Centre, PO Box 574, SE-751 23 Uppsala, Sweden.,National Veterinary Institute (SVA), Department of Chemistry, Environment and Feed Hygiene, SE-751 89 Uppsala, Sweden
| | - John R Barr
- Centers for Disease Control and Prevention, NCEH/DLS, 4770 Buford Hwy NE, Atlanta, GA 30341-3724, USA
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Moura H, Terilli RR, Woolfitt AR, Gallegos-Candela M, McWilliams LG, Solano MI, Pirkle JL, Barr JR. Studies on botulinum neurotoxins type /C1 and mosaic/DC using Endopep-MS and proteomics. ACTA ACUST UNITED AC 2011; 61:288-300. [PMID: 21205003 DOI: 10.1111/j.1574-695x.2010.00774.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Botulinum neurotoxins (BoNTs) are very potent toxins and category A biological threat agents. BoNT serotypes /C1 and /D affect birds and mammals and can be potentially lethal to humans. We have previously described the usefulness of the Endopep-MS method to detect the activity of BoNT A through G. This report was followed by the application of the method to clinical samples. The activity of the BoNT serotypes associated with human disease (/A, /B, /E, and /F) was successfully detected. However, BoNT/C and /D require different conditions for fast substrate cleavage, and a comprehensive description of a method to study BoNT/C and /D has not yet been reported. This work describes a new, optimized version of the Endopep-MS method to detect BoNTs /C1 and /DC either spiked directly in 20 μL of reaction buffer or spiked in a larger volume of buffer and further extracted using antibody-coated magnetic beads. It was found that the incubation temperature at 42 °C was more effective for both toxin serotypes, but each toxin serotype has an optimum cleavage pH. Additionally, we describe for the first time a proteomics study using a fast trypsin digestion method and label-free quantification of these toxin serotypes.
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Affiliation(s)
- Hercules Moura
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
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37
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Torii Y, Akaike N, Harakawa T, Kato K, Sugimoto N, Goto Y, Nakahira S, Kohda T, Kozaki S, Kaji R, Ginnaga A. Type A1 but Not Type A2 Botulinum Toxin Decreases the Grip Strength of the Contralateral Foreleg Through Axonal Transport From the Toxin-Treated Foreleg of Rats. J Pharmacol Sci 2011; 117:275-85. [DOI: 10.1254/jphs.11121fp] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022] Open
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Different substrate recognition requirements for cleavage of synaptobrevin-2 by Clostridium baratii and Clostridium botulinum type F neurotoxins. Appl Environ Microbiol 2010; 77:1301-8. [PMID: 21169446 DOI: 10.1128/aem.01662-10] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) cause botulism, which can be fatal if it is untreated. BoNTs cleave proteins necessary for nerve transmission, resulting in paralysis. The in vivo protein target has been reported for all seven serotypes of BoNT, i.e., serotypes A to G. Knowledge of the cleavage sites has led to the development of several assays to detect BoNT based on its ability to cleave a peptide substrate derived from its in vivo protein target. Most serotypes of BoNT can be subdivided into subtypes, and previously, we demonstrated that three of the currently known subtypes of BoNT/F cleave a peptide substrate, a shortened version of synaptobrevin-2, between Q58 and K59. However, our research indicated that Clostridium baratii type F toxin did not cleave this peptide. In this study, we detail experiments demonstrating that Clostridium baratii type F toxin cleaves recombinant synaptobrevin-2 in the same location as that cleaved by proteolytic F toxin. In addition, we demonstrate that Clostridium baratii type F toxin can cleave a peptide substrate based on the sequence of synaptobrevin-2. This peptide substrate is an N-terminal extension of the original peptide substrate used for detection of other BoNT/F toxins and can be used to detect four of the currently known BoNT/F subtypes by mass spectrometry.
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Dhaked RK, Singh MK, Singh P, Gupta P. Botulinum toxin: bioweapon & magic drug. Indian J Med Res 2010; 132:489-503. [PMID: 21149997 PMCID: PMC3028942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Indexed: 11/22/2022] Open
Abstract
Botulinum neurotoxins, causative agents of botulism in humans, are produced by Clostridium botulinum, an anaerobic spore-former Gram positive bacillus. Botulinum neurotoxin poses a major bioweapon threat because of its extreme potency and lethality; its ease of production, transport, and misuse; and the need for prolonged intensive care among affected persons. A single gram of crystalline toxin, evenly dispersed and inhaled, can kill more than one million people. The basis of the phenomenal potency of botulinum toxin is enzymatic; the toxin is a zinc proteinase that cleaves neuronal vesicle associated proteins responsible for acetylcholine release into the neuromuscular junction. As a military or terrorist weapon, botulinum toxin could be disseminated via aerosol or by contamination of water or food supplies, causing widespread casualties. A fascinating aspect of botulinum toxin research in recent years has been development of the most potent toxin into a molecule of significant therapeutic utility . It is the first biological toxin which is licensed for treatment of human diseases. In the late 1980s, Canada approved use of the toxin to treat strabismus, in 2001 in the removal of facial wrinkles and in 2002, the FDA in the United States followed suit. The present review focuses on both warfare potential and medical uses of botulinum neurotoxin.
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Affiliation(s)
- Ram Kumar Dhaked
- Biotechnology Division, Defence Research & Development Establishment, Gwalior, India.
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40
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Endopeptidase activities of botulinum neurotoxin type B complex, holotoxin, and light chain. Appl Environ Microbiol 2010; 76:6658-63. [PMID: 20693440 DOI: 10.1128/aem.00731-10] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Botulinum neurotoxin (BoNT) serotype B (BoNT/B) is one of the serotypes of BoNT that causes deadly human botulism, though it is used clinically for treatment of many neuromuscular diseases. BoNT/B is produced by Clostridium botulinum, and it is secreted along with a group of neurotoxin-associated proteins (NAPs) in the form of a BoNT/B complex. The complex dissociates into a 150-kDa holotoxin and NAPs at alkaline pHs. The 150-kDa BoNT/B holotoxin can be nicked to produce a 50-kDa domain referred to as the light chain (LC) and a 100-kDa heavy chain, with the former possessing a unique endopeptidase activity. The two chains remain linked through a disulfide bond that can be reduced to separate the two chains. The endopeptidase activity is present in all three forms of the toxin (complex, purified BoNT/B holotoxin, and separated light chain), which are used by different researchers to develop detection methods and screen for inhibitors. In this research, the endopeptidase activities of the three forms, for the first time, were compared under the same conditions. The results show that enzyme activities of the three forms differ significantly and are largely dependent on nicking and disulfide reduction conditions. Under the conditions used, LC had the highest level of activity, and the complex had the lowest. The activity was enhanced by nicking of BoNT/B holotoxin and was enhanced even more by dithiothreitol (DTT) reduction after nicking. This information is useful for understanding the properties of BoNT endopeptidases and for comparing the efficacies of different inhibitors when they are tested with different forms of BoNT endopeptidase.
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41
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Behrensdorf-Nicol HA, Bonifas U, Kegel B, Silberbach K, Krämer B, Weißer K. In vitro determination of tetanus toxicity by an endopeptidase assay linked to a ganglioside-binding step. Toxicol In Vitro 2010; 24:988-94. [DOI: 10.1016/j.tiv.2009.12.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 12/14/2009] [Accepted: 12/18/2009] [Indexed: 11/26/2022]
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Abstract
Sensitive and rapid detection of botulinum neurotoxins (BoNTs), the most poisonous substances known to date, is essential for studies of medical applications of BoNTs and detection of poisoned food, as well as for response to potential bioterrorist threats. Currently, the most common method of BoNT detection is the mouse bioassay. While this assay is sensitive, it is slow, quite expensive, has limited throughput and requires sacrificing animals. Herein, we discuss and compare recently developed alternative in vitro detection methods and assess their ability to supplement or replace the mouse bioassay in the analysis of complex matrix samples.
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Affiliation(s)
- Petr Čapek
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA;
| | - Tobin J. Dickerson
- Department of Chemistry and Worm Institute for Research and Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
- Author to whom correspondence should be addressed; ; Tel.: +1-858-784-2522; Fax: +1-858-784-2590
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43
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Čapek P, Dickerson TJ. Sensing the deadliest toxin: technologies for botulinum neurotoxin detection. Toxins (Basel) 2010; 2:24-53. [PMID: 22069545 PMCID: PMC3206617 DOI: 10.3390/toxins2020024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 12/17/2009] [Accepted: 12/22/2009] [Indexed: 11/16/2022] Open
Abstract
Sensitive and rapid detection of botulinum neurotoxins (BoNTs), the most poisonous substances known to date, is essential for studies of medical applications of BoNTs and detection of poisoned food, as well as for response to potential bioterrorist threats. Currently, the most common method of BoNT detection is the mouse bioassay. While this assay is sensitive, it is slow, quite expensive, has limited throughput and requires sacrificing animals. Herein, we discuss and compare recently developed alternative in vitro detection methods and assess their ability to supplement or replace the mouse bioassay in the analysis of complex matrix samples.
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Affiliation(s)
- Petr Čapek
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA;
| | - Tobin J. Dickerson
- Department of Chemistry and Worm Institute for Research and Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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44
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Kim YJ, Baek JH, Kim JH, Kim BS, Rhie GE, Yoo CK, Shin NR. Detection of Botulinum Neurotoxin Type A by In Vitro Bioassay Based on Endopeptidase Activity. ACTA ACUST UNITED AC 2010. [DOI: 10.4167/jbv.2010.40.1.29] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Yun Jeong Kim
- Division of High-risk Pathogen Research, Center for Infectious Diseases, National Institute of Health, Seoul, Korea
| | - Joung Hee Baek
- Division of High-risk Pathogen Research, Center for Infectious Diseases, National Institute of Health, Seoul, Korea
| | - Jeong-Hee Kim
- Division of High-risk Pathogen Research, Center for Infectious Diseases, National Institute of Health, Seoul, Korea
| | - Bong Su Kim
- Division of High-risk Pathogen Research, Center for Infectious Diseases, National Institute of Health, Seoul, Korea
| | - Gi-eun Rhie
- Division of High-risk Pathogen Research, Center for Infectious Diseases, National Institute of Health, Seoul, Korea
| | - Cheon-Kwon Yoo
- Division of High-risk Pathogen Research, Center for Infectious Diseases, National Institute of Health, Seoul, Korea
| | - Na-Ri Shin
- Division of High-risk Pathogen Research, Center for Infectious Diseases, National Institute of Health, Seoul, Korea
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Moghaddam MM, Mousavi L, Shokrgozar MA, Amani J, Nazariyan S, Azari S. Cloning and expression of a region of vesicle associated membrane protein2 (VAMP2) gene and its use as a recombinant peptide substrate for assaying clostridial neurotoxins in contaminated biologicals. Biologicals 2009; 38:113-9. [PMID: 20005125 DOI: 10.1016/j.biologicals.2009.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2009] [Revised: 04/08/2009] [Accepted: 04/11/2009] [Indexed: 01/22/2023] Open
Abstract
An assay for the endopeptidase activities of clostridial neurotoxins in contaminated biotherapeutic products has been developed. Based on a synthetic peptide substrate representing amino acid residues 60-94 of the intracellular vesicle associated membrane protein2 (VAMP2), RT-PCR was used to amplify the VAMP2 sequence. The extended insert was digested with EcoRI and SalI and ligated into pGEX4T-1 vector for construction of the pGEX4T-1/VAMP plasmid for expressing in Escherichia coli a fusion protein linked to glutathione S-transferase (GST). The fusion protein was purified by affinity chromatography and used in an ELISA assay for comparison with the commercially available synthetic VAMP peptide and rabbit polyclonal antiserum. The identity of the immunoreactivity of recombinant VAMP2 protein with the chemically synthesized peptide was demonstrated by western blot. Our results indicated that recombinant VAMP2 peptide not only reacted with specific polyclonal antibody in a dose-dependent manner, without any remarkable difference observed between the reactivity of the fusion protein and commercial VAMP2 segment peptide, but also cleaved by botulinum neurotoxin type B (BONT/B) after endopeptidase assay. Thus, recombinant VAMP2 could serve as a replacement for VAMP2 synthetic peptide, potentially useful in endopeptidase assays for replacement of the currently used mouse bioassay for clostridial neurotoxins contaminating biotherapeutic products.
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Sakamoto T, Torii Y, Takahashi M, Ishida S, Goto Y, Nakano H, Harakawa T, Ginnaga A, Kozaki S, Kaji R. Quantitative determination of the biological activity of botulinum toxin type A by measuring the compound muscle action potential (CMAP) in rats. Toxicon 2009; 54:857-61. [DOI: 10.1016/j.toxicon.2009.06.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 06/12/2009] [Accepted: 06/16/2009] [Indexed: 11/28/2022]
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Torii Y, Goto Y, Takahashi M, Ishida S, Harakawa T, Sakamoto T, Kaji R, Kozaki S, Ginnaga A. Quantitative determination of biological activity of botulinum toxins utilizing compound muscle action potentials (CMAP), and comparison of neuromuscular transmission blockage and muscle flaccidity among toxins. Toxicon 2009; 55:407-14. [PMID: 19778548 DOI: 10.1016/j.toxicon.2009.09.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 08/18/2009] [Accepted: 09/15/2009] [Indexed: 11/28/2022]
Abstract
The biological activity of various types of botulinum toxin has been evaluated using the mouse intraperitoneal LD(50) test (ip LD(50)). This method requires a large number of mice to precisely determine toxin activity, and so has posed a problem with regard to animal welfare. We have used a direct measure of neuromuscular transmission, the compound muscle action potential (CMAP), to evaluate the effect of different types of botulinum neurotoxin (NTX), and we compared the effects of these toxins to evaluate muscle relaxation by employing the digit abduction scoring (DAS) assay. This method can be used to measure a broad range of toxin activities the day after administration. Types A, C, C/D, and E NTX reduced the CMAP amplitude one day after administration at below 1 ip LD(50), an effect that cannot be detected using the mouse ip LD(50) assay. The method is useful not only for measuring toxin activity, but also for evaluating the characteristics of different types of NTX. The rat CMAP test is straightforward, highly reproducible, and can directly determine the efficacy of toxin preparations through their inhibition of neuromuscular transmission. Thus, this method may be suitable for pharmacology studies and the quality control of toxin preparations.
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Affiliation(s)
- Yasushi Torii
- The Chemo-Sero-Therapeutic Research Institute (KAKETSUKEN), 1-6-1 Okubo, Kumamoto-shi, Kumamoto 860-8568, Japan.
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Salzameda NT, Barbieri JT, Janda KD. Synthetic substrate for application in both high and low throughput assays for botulinum neurotoxin B protease inhibitors. Bioorg Med Chem Lett 2009; 19:5848-50. [PMID: 19747823 DOI: 10.1016/j.bmcl.2009.08.079] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 08/20/2009] [Accepted: 08/24/2009] [Indexed: 10/20/2022]
Abstract
A FRET peptide substrate was synthesized and evaluated for enzymatic cleavage by the BoNT/B light chain protease. The FRET substrate was found to be useful in both a high throughput assay to uncover initial 'hits' and a low throughput HPLC assay to determine kinetic parameters and modes of inhibition.
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Affiliation(s)
- Nicholas T Salzameda
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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49
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Detection and quantification of botulinum neurotoxin type a by a novel rapid in vitro fluorimetric assay. Appl Environ Microbiol 2009; 75:4382-90. [PMID: 19429547 DOI: 10.1128/aem.00091-09] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Botulinum neurotoxin type A (BoNT/A), the most poisonous substance known to humans, is a potential bioterrorism agent. The light-chain protein induces a flaccid paralysis through cleavage of the 25-kDa synaptosome-associated protein (SNAP-25), involved in acetylcholine release at the neuromuscular junction. BoNT/A is widely used as a therapeutic agent and to reduce wrinkles. The toxin is used at very low doses, which have to be accurately quantified. With this aim, internally quenched fluorescent substrates containing the fluorophore/repressor pair pyrenylalanine (Pya)/4-nitrophenylalanine (Nop) were developed. Nop and Pya were, respectively, introduced at positions 197 and 200 of the cleavable fragment (amino acids 187 to 203) of SNAP-25 (with norleucine at position 202 [Nle(202)]), which is acetylated at its N terminus and amidated at its C terminus. Cleavage of this peptide occurred between positions 197 and 198, as in SNAP-25, and was easily quantified by the strong fluorescence emission of the metabolite. To increase the assay sensitivity, the peptide sequence of the previous substrate was lengthened to account for exosite binding to BoNT/A. We synthesized the peptide PL50 (SNAP-25-NH(2) acetylated at positions 156 to 203 [Nop(197), Pya(200), Nle(202)]) and its analogue PL51, in which all methionines were replaced by nonoxidizable Nle. Consistent with a large increase in affinity for BoNT/A, PL50 and PL51 exhibit catalytic efficiencies of 2.6 x 10(6) M(-1) s(-1) and 8.85 x 10(6) M(-1) s(-1), respectively, and behave as the best fluorigenic substrates of BoNT/A reported to date. Under optimized assay conditions, they allow simple quantification of as little as 100 and 60 pg of BoNT/A, respectively, within 2 h with a classical fluorimeter. Calibration of the method against the mouse 50% lethal dose assay unequivocally validates the enzymatic assay.
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50
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Bivalent recombinant vaccine for botulinum neurotoxin types A and B based on a polypeptide comprising their effector and translocation domains that is protective against the predominant A and B subtypes. Infect Immun 2009; 77:2795-801. [PMID: 19398544 DOI: 10.1128/iai.01252-08] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The botulinum neurotoxins (BoNTs) are a large family of extremely potent, neuroparalytic, dichain proteins which act at the peripheral nervous system. The wide genetic diversity observed with this neurotoxin family poses a significant challenge for the development of an effective botulinum vaccine. The present study describes a vaccine development platform based on protein fragments representing the N-terminal two-thirds of each toxin molecule. These fragments, designated LH(N), comprise the light chain and translocation domains of each neurotoxin and are devoid of any neuron-binding activity. Using codon-optimized genes, LH(N) fragments derived from BoNT serotypes A and B were expressed in Escherichia coli in high yield with >1 g of purified, soluble fragment recoverable from 4.5 liter-scale fermentations. The protective efficacy of LH(N)/A was significantly enhanced by treatment with formaldehyde, which induced intramolecular cross-linking but virtually no aggregation of the fragment. A single immunization of the modified fragment protected mice from challenge with a 10(3) 50% lethal dose (LD(50)) of BoNT/A(1) with an 50% effective dose (ED(50)) of 50 ng of the vaccine. In similar experiments, the LH(N)/A vaccine was shown to protect mice against challenge with BoNT/A subtypes A(1), A(2), and A(3), which is the first demonstration of single-dose protection by a vaccine against the principal toxin subtypes of BoNT/A. The LH(N)/B vaccine was also highly efficacious, giving an ED(50) of approximately 140 ng to a challenge of 10(3) LD(50) of BoNT/B(1). In addition, LH(N)/B provided single-dose protection in mice against BoNT/B(4) (nonproteolytic toxin subtype).
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