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Lee J, Brennan MB, Wilton R, Rowland CE, Rozhkova EA, Forrester S, Hannah DC, Carlson J, Shevchenko EV, Schabacker DS, Schaller RD. Fast, Ratiometric FRET from Quantum Dot Conjugated Stabilized Single Chain Variable Fragments for Quantitative Botulinum Neurotoxin Sensing. NANO LETTERS 2015; 15:7161-7167. [PMID: 26397120 DOI: 10.1021/acs.nanolett.5b03442] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Botulinum neurotoxin (BoNT) presents a significant hazard under numerous realistic scenarios. The standard detection scheme for this fast-acting toxin is a lab-based mouse lethality assay that is sensitive and specific, but slow (∼2 days) and requires expert administration. As such, numerous efforts have aimed to decrease analysis time and reduce complexity. Here, we describe a sensitive ratiometric fluorescence resonance energy transfer scheme that utilizes highly photostable semiconductor quantum dot (QD) energy donors and chromophore conjugation to compact, single chain variable antibody fragments (scFvs) to yield a fast, fieldable sensor for BoNT with a 20-40 pM detection limit, toxin quantification, adjustable dynamic range, sensitivity in the presence of interferents, and sensing times as fast as 5 min. Through a combination of mutations, we achieve stabilized scFv denaturation temperatures of more than 60 °C, which bolsters fieldability. We also describe adaptation of the assay into a microarray format that offers persistent monitoring, reuse, and multiplexing.
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Affiliation(s)
- Joonseok Lee
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Melissa B Brennan
- Biosciences, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Rosemarie Wilton
- Biosciences, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Clare E Rowland
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Elena A Rozhkova
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Sara Forrester
- Global Security Sciences, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Daniel C Hannah
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Julia Carlson
- College of Agricultural & Life Sciences, University of Wisconsin , Madison, Wisconsin 53706, United States
| | - Elena V Shevchenko
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Daniel S Schabacker
- Global Security Sciences, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Richard D Schaller
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
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Ben David A, Torgeman A, Barnea A, Zichel R. Expression, purification and characterization of the receptor-binding domain of botulinum neurotoxin serotype B as a vaccine candidate. Protein Expr Purif 2015; 110:122-9. [PMID: 25727047 DOI: 10.1016/j.pep.2015.02.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 02/08/2015] [Accepted: 02/09/2015] [Indexed: 11/28/2022]
Abstract
The receptor-binding domain of botulinum neurotoxins (the HC fragment) is a promising vaccine candidate. Among the HC fragments of the seven BoNT serotypes, the expression of HC/B in Escherichia coli is considered especially challenging due to its accumulation as a non-soluble protein aggregate. In this study, the effects of different parameters on the expression of soluble HC/B were evaluated using a screening assay that included growing the bacterium at a small scale, a chemical cell lysis step, and a specific ELISA. The highest soluble HC/B expression levels were obtained when the bacterium E. coli BL21(DE3)+pET-9a-HC/B was grown in terrific broth media at 18°C without induction. Under these conditions, the yield was an order of magnitude higher than previously reported. Standard purification of the protein using a nickel column resulted in a low purity of HC/B. However, the addition of an acidic wash step prior to protein elution released a major protein contaminant and significantly increased the purity level. Mass spectrometry analysis identified the contaminant as ArnA, an E. coli protein that often contaminates recombinant His-tagged protein preparations. The purified HC/B was highly immunogenic, protecting mice from a 10(6) LD50 challenge after a single vaccination and generating a neutralizing titer of 50IU/ml after three immunizations. Moreover, the functionality of the protein was preserved, as it inhibited BoNT/B intoxication in vivo, presumably due to blockade of the neurotoxin protein receptor synaptotagmin.
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Affiliation(s)
- Alon Ben David
- Department of Biotechnology, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Amram Torgeman
- Department of Biotechnology, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Ada Barnea
- Department of Biotechnology, Israel Institute for Biological Research, Ness Ziona, Israel
| | - Ran Zichel
- Department of Biotechnology, Israel Institute for Biological Research, Ness Ziona, Israel.
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The receptor binding domain of botulinum neurotoxin serotype A (BoNT/A) inhibits BoNT/A and BoNT/E intoxications in vivo. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2013; 20:1266-73. [PMID: 23761665 DOI: 10.1128/cvi.00268-13] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The receptor binding domain of botulinum neurotoxin (BoNT), also designated the C terminus of the heavy chain (H(C)), is a promising vaccine candidate against botulism. In this study, a highly efficient expression system for the protein was developed in Escherichia coli, which provided yields that were 1 order of magnitude higher than those reported to date (350 mg H(C) per liter). The product was highly immunogenic, protecting mice from a challenge with 10(5) 50% lethal dose (LD(50)) after a single vaccination and generating a neutralizing titer of 49.98 IU/ml after three immunizations. In addition, a single boost with HC increased neutralizing titers by up to 1 order of magnitude in rabbits hyperimmunized against toxoid. Moreover, we demonstrate here for the first time in vivo inhibition of BoNT/A intoxication by H(C)/A, presumably due to a blockade of the neurotoxin protein receptor SV2. Administration of HC/A delayed the time to death from 10.4 to 27.3 h in mice exposed to a lethal dose of BoNT/A (P = 0.0005). Since BoNT/A and BoNT/E partially share SV2 isoforms as their protein receptors, the ability of H(C)/A to cross-inhibit BoNT/E intoxication was evaluated. The administration of H(C)/A together with BoNT/E led to 50% survival and significantly delayed the time to death for the nonsurviving mice (P = 0.003). Furthermore, a combination of H(C)/A and a subprotective dose of antitoxin E fully protected mice against 850 mouse LD(50) of BoNT/E, suggesting complementary mechanisms of protection consisting of toxin neutralization by antibodies and receptor blocking by H(C)/A.
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Recombinant proteins that trigger production of antibodies recognizing botulinum neurotoxin while not possessing sequences of this toxin. Toxicon 2013; 67:63-70. [DOI: 10.1016/j.toxicon.2013.02.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 02/11/2013] [Accepted: 02/22/2013] [Indexed: 11/20/2022]
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Villaflores OB, Hsei CM, Teng CY, Chen YJ, Wey JJ, Tsui PY, Shyu RH, Tung KL, Yeh JM, Chiao DJ, Wu TY. Easy expression of the C-terminal heavy chain domain of botulinum neurotoxin serotype A as a vaccine candidate using a bi-cistronic baculovirus system. J Virol Methods 2013; 189:58-64. [PMID: 23313783 DOI: 10.1016/j.jviromet.2012.11.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Revised: 11/18/2012] [Accepted: 11/21/2012] [Indexed: 10/27/2022]
Abstract
Clostridial botulinum neurotoxin (BoNT) is one of the most toxic proteins causing the food borne disease, botulism. In previous studies, recombinant BoNT production by Escherichia coli and yeast Pichia pastoris has been hampered by high AT content and codon bias in the gene encoding BoNT and required a synthetic gene to resolve this intrinsic bottleneck. This paper reports the simultaneous expression of the C-terminal heavy chain domain of BoNT (rBoNT/A-HC-6h) and enhanced green fluorescent protein (EGFP) using a bi-cistronic baculovirus-insect cell expression system. The expression of EGFP facilitated the monitoring of viral infection, virus titer determination, and isolation of the recombinant virus. Protein fusion with hexa-His-tag and one-step immobilized metal-ion affinity chromatography (IMAC) purification produced a homogenous, stable, and immunologically active 55-kDa rBoNT/A-HC-6h (about 3mg/L) with >90% purity. Furthermore, measured levels of serum titers were 8-folds for mice vaccinated with the purified rBoNT/A-HC-6h (2μg) than for mice administered with botulinum toxoid after initial immunization. Challenge experiment with botulinum A toxin demonstrated the immunoprotective activity of purified rBoNT/A-HC-6h providing the mice full protection against 10(2) LD50 botulinum A toxin with a dose as low as 0.2μg. This study provided supportive evidence for the use of a bi-cistronic baculovirus-Sf21 insect cell expression system in the facile expression of an immunogenically active rBoNT/A-HC.
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Yari K, Fatemi SSA, Tavallaei M. High level expression of recombinant BoNT/A-Hc by high cell density cultivation of Escherichia coli. Bioprocess Biosyst Eng 2011; 35:407-14. [DOI: 10.1007/s00449-011-0579-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 07/22/2011] [Indexed: 11/24/2022]
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Cai K, Gao X, Li T, Wang Q, Hou X, Tu W, Xiao L, Tian M, Liu Y, Wang H. Enhanced immunogenicity of a novel Stx2Am-Stx1B fusion protein in a mice model of enterohemorrhagic Escherichia coli O157:H7 infection. Vaccine 2011; 29:946-52. [DOI: 10.1016/j.vaccine.2010.11.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 10/22/2010] [Accepted: 11/14/2010] [Indexed: 10/18/2022]
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