1
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Eilts F, Harsy YMJ, Lothert K, Pagallies F, Amann R, Wolff MW. An investigation of excipients for a stable Orf viral vector formulation. Virus Res 2023; 336:199213. [PMID: 37657509 PMCID: PMC10495626 DOI: 10.1016/j.virusres.2023.199213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 08/27/2023] [Accepted: 08/29/2023] [Indexed: 09/03/2023]
Abstract
The Orf virus (ORFV) is a promising candidate for vector vaccines as well as for immunomodulatory and oncolytic therapies. However, few publications are available on its infectivity degradation or on suitable additives for prolonging its viral stability. In this study, the non-supplemented ORFV itself showed a very high stability at storage temperatures up to 28 °C, with a linear titer loss of 0.10 log infectious particles per day at 4 °C over a period of five weeks. To prolong this inherent stability, thirty additives, i.e., detergents, sugars, proteins, salts, and buffers as well as amino acids, were tested for their time- and temperature-dependent influence on the ORFV infectivity. A stabilizing effect on the infectivity was identified for the addition of all tested proteins, i.e., gelatine, bovine serum albumin, and recombinant human serum albumin (rHSA), of several sugars, i.e., mannitol, galactose, sucrose, and trehalose, of amino acids, i.e., arginine and proline, of the detergent Pluronic F68, and of the salt Na2SO4. The infectivity preservation was especially pronounced for proteins in liquid and frozen formulations, sugars in frozen state, and arginine und Pluronic in liquid formulations at high storage temperatures (37 °C). The addition of 1% rHSA with and without 5% sucrose was evaluated as a very stable formulation with a high safety profile and economic validity at storage temperatures up to 28 °C. At increased temperatures, the supplementation with 200 mM arginine performed better than with rHSA. In summary, this comprehensive data provides different options for a stable ORFV formulation, considering temperature, storage time, economic aspects, and downstream processing integrity.
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Affiliation(s)
- Friederike Eilts
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, Giessen 35390, Germany
| | - Yasmina M J Harsy
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, Giessen 35390, Germany
| | - Keven Lothert
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, Giessen 35390, Germany
| | - Felix Pagallies
- Department of Immunology, University of Tuebingen, Auf der Morgenstelle 15, Tuebingen 72076, Germany
| | - Ralf Amann
- Department of Immunology, University of Tuebingen, Auf der Morgenstelle 15, Tuebingen 72076, Germany; PRiME Vector Technologies, Herrenberger Straße 24, Tuebingen 72070, Germany
| | - Michael W Wolff
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, Giessen 35390, Germany.
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2
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Eilts F, Labisch JJ, Orbay S, Harsy YMJ, Steger M, Pagallies F, Amann R, Pflanz K, Wolff MW. Stability studies for the identification of critical process parameters for a pharmaceutical production of the Orf virus. Vaccine 2023:S0264-410X(23)00722-3. [PMID: 37353451 DOI: 10.1016/j.vaccine.2023.06.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 06/01/2023] [Accepted: 06/12/2023] [Indexed: 06/25/2023]
Abstract
A promising new vaccine platform is based on the Orf virus, a viral vector of the genus Parapoxvirus, which is currently being tested in phase I clinical trials. The application as a vaccine platform mandates a well-characterised, robust, and efficient production process. To identify critical process parameters in the production process affecting the virus' infectivity, the Orf virus was subjected to forced degradation studies, including thermal, pH, chemical, and mechanical stress conditions. The tests indicated a robust virus infectivity within a pH range of 5-7.4 and in the presence of the tested buffering substances (TRIS, HEPES, PBS). The ionic strength up to 0.5 M had no influence on the Orf virus' infectivity stability for NaCl and MgCl2, while NH4Cl destabilized significantly. Furthermore, short-term thermal stress of 2d up to 37 °C and repeated freeze-thaw cycles (20cycles) did not affect the virus' infectivity. The addition of recombinant human serum albumin was found to reduce virus inactivation. Last, the Orf virus showed a low shear sensitivity induced by peristaltic pumps and mixing, but was sensitive to ultrasonication. The isoelectric point of the applied Orf virus genotype D1707-V was determined at pH3.5. The broad picture of the Orf virus' infectivity stability against environmental parameters is an important contribution for the identification of critical process parameters for the production process, and supports the development of a stable pharmaceutical formulation. The work is specifically relevant for enveloped (large DNA) viruses, like the Orf virus and like most vectored vaccine approaches.
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Affiliation(s)
- Friederike Eilts
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany
| | - Jennifer J Labisch
- Lab Essentials Applications Development, Sartorius Stedim Biotech GmbH, August-Spindler-Straße 11, 37079 Goettingen, Germany; Institute of Technical Chemistry, Leibniz University Hannover, Callinstraße 3-9, 30167 Hannover, Lower Saxony, Germany
| | - Sabri Orbay
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany
| | - Yasmina M J Harsy
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany
| | - Marleen Steger
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany
| | - Felix Pagallies
- Department of Immunology, University of Tuebingen, Auf der Morgenstelle 15/3.008, 72076 Tuebingen, Germany
| | - Ralf Amann
- Department of Immunology, University of Tuebingen, Auf der Morgenstelle 15/3.008, 72076 Tuebingen, Germany; Prime Vector Technologies, Herrenberger Straße 24, 72070 Tuebingen, Germany
| | - Karl Pflanz
- Lab Essentials Applications Development, Sartorius Stedim Biotech GmbH, August-Spindler-Straße 11, 37079 Goettingen, Germany
| | - Michael W Wolff
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany.
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3
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Wang L. Diagnostics for Viral Pathogens in Veterinary Diagnostic Laboratories. Vet Clin North Am Food Anim Pract 2023; 39:129-140. [PMID: 36731993 DOI: 10.1016/j.cvfa.2022.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Laboratory testing is one part of clinical diagnosis, and quick and reliable testing results provide important data to support treatment decision and develop control strategies. Clinical viral testing has been shifting from traditional virus isolation and electron microscopy to molecular polymerase chain reaction and point-of-care antigen tests. This shift in diagnostic methodology also means change from looking for infectious virions or viral particles to hunting viral antigens and genomes. With technological development, it is predicted that metagenomic sequencing will be commonly used in veterinary clinical diagnosis for unveiling the whole picture of microbes involved in diseases in the future.
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Affiliation(s)
- Leyi Wang
- Department of Veterinary Clinical Medicine, Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, VMBSB Room 1222A, Urbana, IL 61802, USA.
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4
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Eilts F, Steger M, Pagallies F, Rziha HJ, Hardt M, Amann R, Wolff MW. Comparison of sample preparation techniques for the physicochemical characterization of Orf virus particles. J Virol Methods 2022; 310:114614. [PMID: 36084768 DOI: 10.1016/j.jviromet.2022.114614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/04/2022] [Accepted: 09/05/2022] [Indexed: 12/24/2022]
Abstract
The determination of the electrostatic charge of biological nanoparticles requires a purified, mono-disperse, and concentrated sample. Previous studies proofed an impact of the preparation protocol on the stability and electro-hydrodynamics of viruses, whereas commonly used methods are often complex and do not allow the required sample throughput. In the present study, the application of the (I) steric exclusion chromatography (SXC) for the Orf virus (ORFV) purification and subsequent physicochemical characterization was evaluated and compared to (II) SXC followed by centrifugal diafiltration and (III) sucrose cushion ultracentrifugation. The three methods were characterized in terms of protein removal, size distribution, infectious virus recovery, visual appearance, and electrophoretic mobility as a function of pH. All preparation techniques achieved a protein removal of more than 99 %, and (I) an infectious ORFV recovery of more than 85 %. Monodisperse samples were realized by (I) and (III). In summary, ORFV samples prepared by (I) and (III) displayed comparable quality. Additionally, (I) offered the shortest operation time and easy application. Based on the obtained data, the three procedures were ranked according to eight criteria of possible practical relevance, which delineate the potential of SXC as virus preparation method for physicochemical analysis.
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Affiliation(s)
- Friederike Eilts
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany.
| | - Marleen Steger
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany
| | - Felix Pagallies
- Department of Immunology, University of Tuebingen, Auf der Morgenstelle 15, 72076 Tuebingen, Germany
| | - Hanns-Joachim Rziha
- Department of Immunology, University of Tuebingen, Auf der Morgenstelle 15, 72076 Tuebingen, Germany
| | - Martin Hardt
- Imaging Unit, Biomedical Research Centre Seltersberg, Justus Liebig University, Schubertstraße 81, 35392 Giessen, Germany
| | - Ralf Amann
- Department of Immunology, University of Tuebingen, Auf der Morgenstelle 15, 72076 Tuebingen, Germany; PRiME Vector Technologies, Herrenberger Straße 24, 72070 Tuebingen, Germany
| | - Michael W Wolff
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany; Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Ohlebergsweg 12, 35392 Giessen, Germany.
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5
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Eilts F, Lothert K, Orbay S, Pagallies F, Amann R, Wolff MW. A Summary of Practical Considerations for the Application of the Steric Exclusion Chromatography for the Purification of the Orf Viral Vector. MEMBRANES 2022; 12:1070. [PMID: 36363625 PMCID: PMC9696199 DOI: 10.3390/membranes12111070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/18/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
Steric exclusion chromatography (SXC) is a promising purification method for biological macromolecules such as the Orf virus (ORFV) vector. The method's principle is closely related to conventional polyethylene glycol (PEG) precipitation, repeatedly implementing membranes as porous chromatographic media. In the past decade, several purification tasks with SXC showed exceptionally high yields and a high impurity removal. However, the effect of varying process parameters, on the precipitation success and its limitations to SXC, is not yet well understood. For this reason, the precipitation behavior and SXC adaptation for ORFV were investigated for the PEG/ORFV contact time, the membranes pore size, and the type and concentration of ions. All three parameters influenced the ORFV recoveries significantly. A small pore size and a long contact time induced filtration effects and inhibited a full virus recovery. The application of salts had complex concentration-dependent effects on precipitation and SXC yields, and ranged from a complete prevention of precipitation in the presence of kosmotropic substances to increased efficiencies with Mg2+ ions. The latter finding might be useful to reduce PEG concentrations while maintaining high yields. With this knowledge, we hope to clarify several limitations of SXC operations and improve the tool-set for a successful process adaptation.
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Affiliation(s)
- Friederike Eilts
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany
| | - Keven Lothert
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany
| | - Sabri Orbay
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany
| | - Felix Pagallies
- Department of Immunology, University of Tuebingen, Auf der Morgenstelle 15, 72076 Tuebingen, Germany
| | - Ralf Amann
- Department of Immunology, University of Tuebingen, Auf der Morgenstelle 15, 72076 Tuebingen, Germany
- PRiME Vector Technologies, Herrenberger Straße 24, 72070 Tuebingen, Germany
| | - Michael W. Wolff
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen (THM), Wiesenstr.14, 35390 Giessen, Germany
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Ohlebergsweg 12, 35392 Giessen, Germany
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6
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Milrot E, Makdasi E, Politi B, Israely T, Laskar O. A Cell-Based Capture Assay for Rapid Virus Detection. Viruses 2020; 12:v12101165. [PMID: 33076296 PMCID: PMC7602404 DOI: 10.3390/v12101165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 10/08/2020] [Accepted: 10/13/2020] [Indexed: 12/20/2022] Open
Abstract
Routine methods for virus detection in clinical specimens rely on a variety of sensitive methods, such as genetic, cell culture and immuno-based assays. It is imperative that the detection assays would be reliable, reproducible, sensitive and rapid. Isolation of viruses from clinical samples is crucial for deeper virus identification and analysis. Here we introduce a rapid cell-based assay for isolation and detection of viruses. As a proof of concept several model viruses including West Nile Virus (WNV), Modified Vaccinia Ankara (MVA) and Adenovirus were chosen. Suspended Vero cells were employed to capture the viruses following specific antibody labeling which enables their detection by flow cytometry and immuno-fluorescence microscopy assays. Using flow cytometry, a dose response analysis was performed in which 3.6e4 pfu/mL and 1e6 pfu/mL of MVA and WNV could be detected within two hours, respectively. When spiked to commercial pooled human serum, detection sensitivity was slightly reduced to 3e6 pfu/mL for WNV, but remained essentially the same for MVA. In conclusion, the study demonstrates a robust and rapid methodology for virus detection using flow cytometry and fluorescence microscopy. We propose that this proof of concept may prove useful in identifying future pathogens.
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7
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Khan MSI, Oh SW, Kim YJ. Power of Scanning Electron Microscopy and Energy Dispersive X-Ray Analysis in Rapid Microbial Detection and Identification at the Single Cell Level. Sci Rep 2020; 10:2368. [PMID: 32047250 PMCID: PMC7012924 DOI: 10.1038/s41598-020-59448-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 01/29/2020] [Indexed: 01/28/2023] Open
Abstract
The demand for rapid, consistent and easy-to-use techniques for detecting and identifying pathogens in various areas, such as clinical diagnosis, the pharmaceutical industry, environmental science and food inspection, is very important. In this study, the reference strains of six food-borne pathogens, namely, Escherichia coli 0157: H7 ATCC 43890, Cronobacter sakazakii ATCC 29004, Salmonella Typhimurium ATCC 43971, Staphylococcus aureus KCCM 40050, Bacillus subtilis ATCC 14579, and Listeria monocytogenes ATCC 19115, were chosen for scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. In our study, the time-consuming sample preparation step for the microbial analysis under SEM was avoided, which makes this detection process notably rapid. Samples were loaded onto a 0.01-µm-thick silver (Ag) foil surface to avoid any charging effect. Two different excitation voltages, 10 kV and 5 kV, were used to determine the elemental information. Information obtained from SEM-EDX can distinguish individual single cells and detect viable and nonviable microorganisms. This work demonstrates that the combination of morphological and elemental information obtained from SEM-EDX analysis with the help of principal component analysis (PCA) enables the rapid identification of single microbial cells without following time-consuming microbiological cultivation methods.
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Affiliation(s)
- Muhammad Saiful Islam Khan
- Korea Food Research Institute, Consumer Safety Research Division, 55365, Wanju-Gun, Jeollabuk-Do, Republic of Korea
| | - Se-Wook Oh
- Department of Food and Nutrition, Kookmin University, 77 Jeongneung-ro, Seongbuk-gu, Seoul, 02707, Republic of Korea
| | - Yun-Ji Kim
- Korea Food Research Institute, Consumer Safety Research Division, 55365, Wanju-Gun, Jeollabuk-Do, Republic of Korea. .,Department of Food Biotechnology, University of Science and Technology, Daejeon, 305-350, Republic of Korea.
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8
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Gelderblom HR, Madeley D. Rapid Viral Diagnosis of Orthopoxviruses by Electron Microscopy: Optional or a Must? Viruses 2018; 10:E142. [PMID: 29565285 PMCID: PMC5923436 DOI: 10.3390/v10040142] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 02/22/2018] [Accepted: 02/22/2018] [Indexed: 12/20/2022] Open
Abstract
Diagnostic electron microscopy (DEM) was an essential component of viral diagnosis until the development of highly sensitive nucleic acid amplification techniques (NAT). The simple negative staining technique of DEM was applied widely to smallpox diagnosis until the world-wide eradication of the human-specific pathogen in 1980. Since then, the threat of smallpox re-emerging through laboratory escape, molecular manipulation, synthetic biology or bioterrorism has not totally disappeared and would be a major problem in an unvaccinated population. Other animal poxviruses may also emerge as human pathogens. With its rapid results (only a few minutes after arrival of the specimen), no requirement for specific reagents and its "open view", DEM remains an important component of virus diagnosis, particularly because it can easily and reliably distinguish smallpox virus or any other member of the orthopoxvirus (OPV) genus from parapoxviruses (PPV) and the far more common and less serious herpesviruses (herpes simplex and varicella zoster). Preparation, enrichment, examination, internal standards and suitable organisations are discussed to make clear its continuing value as a diagnostic technique.
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Affiliation(s)
- Hans R Gelderblom
- (ret) Robert Koch Institute, Centre for Biological Threats and Special Pathogens, ZBS 4: Advanced Light and Electron Microscopy, Seestrasse 10, D-13353 Berlin, Germany.
| | - Dick Madeley
- (ret) University of Newcastle upon Tyne, Burnfoot, Stocksfield, Northumberland, NE43 7TN, UK.
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9
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Golding CG, Lamboo LL, Beniac DR, Booth TF. The scanning electron microscope in microbiology and diagnosis of infectious disease. Sci Rep 2016; 6:26516. [PMID: 27212232 PMCID: PMC4876401 DOI: 10.1038/srep26516] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 05/03/2016] [Indexed: 11/29/2022] Open
Abstract
Despite being an excellent tool for investigating ultrastructure, scanning electron microscopy (SEM) is less frequently used than transmission electron microscopy for microbes such as viruses or bacteria. Here we describe rapid methods that allow SEM imaging of fully hydrated, unfixed microbes without using conventional sample preparation methods. We demonstrate improved ultrastructural preservation, with greatly reduced dehydration and shrinkage, for specimens including bacteria and viruses such as Ebola virus using infiltration with ionic liquid on conducting filter substrates for SEM.
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10
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Beniac DR, Hiebert SL, Siemens CG, Corbett CR, Booth TF. A mobile biosafety microanalysis system for infectious agents. Sci Rep 2015; 5:9505. [PMID: 25820944 PMCID: PMC4377622 DOI: 10.1038/srep09505] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 03/03/2015] [Indexed: 11/10/2022] Open
Abstract
Biological threats posed by pathogens such as Ebola virus must be quickly diagnosed, while protecting the safety of personnel. Scanning electron microscopy and microanalysis requires minimal specimen preparation and can help to identify hazardous agents or substances. Here we report a compact biosafety system for rapid imaging and elemental analysis of specimens, including powders, viruses and bacteria, which is easily transportable to the site of an incident.
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Affiliation(s)
- Daniel R Beniac
- National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, Manitoba. R3E 3R2, Canada
| | - Shannon L Hiebert
- National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, Manitoba. R3E 3R2, Canada
| | - Christine G Siemens
- National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, Manitoba. R3E 3R2, Canada
| | - Cindi R Corbett
- 1] National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, Manitoba. R3E 3R2, Canada [2] Department of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba. R3E 0W3, Canada
| | - Tim F Booth
- 1] National Microbiology Laboratory, Public Health Agency of Canada, 1015 Arlington Street, Winnipeg, Manitoba. R3E 3R2, Canada [2] Department of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba. R3E 0W3, Canada
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11
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Abstract
With the eradication of smallpox about 30 years ago, the identification and differentiation of other poxviruses with varying pathogenicity in humans present a challenge for diagnostic facilities. While a clinical differentiation can be demanding, electron microscopy is the fastest approach to identify poxviruses. Molecular techniques, based on specific genomic sequences, are routinely applied to identify poxvirus species and distinguish between individual virus variants. In this chapter, we present detailed protocols for both techniques and discuss questions relevant to fast and reliable diagnostics of poxviruses.
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Affiliation(s)
- Andreas Kurth
- Centre for Biological Safety 1, German Consultant Laboratory for Poxviruses, Robert Koch Institute, Berlin, Germany
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12
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Laue M, Bannert N. Detection limit of negative staining electron microscopy for the diagnosis of bioterrorism-related micro-organisms. J Appl Microbiol 2010; 109:1159-68. [PMID: 20456527 PMCID: PMC7197746 DOI: 10.1111/j.1365-2672.2010.04737.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Aims: To determine the detection limit of diagnostic negative staining electron microscopy for the diagnosis of pathogens that could be used for bioterrorism. Methods and Results: Suspensions of vaccinia poxvirus and endospores of Bacillus subtilis were used at defined concentrations as a model for poxviruses and spores of anthrax (Bacillus anthracis), both of which are pathogens that could be used for bioterrorist attacks. Negative staining electron microscopy was performed directly or after sedimentation of these suspensions on to the sample supports using airfuge ultracentrifugation. For both virus and spores, the detection limit using direct adsorption of a 10‐μl sample volume onto the sample support was 106 particles per ml. Using airfuge ultracentrifugation with a sample volume of 80 μl, the detection limit could be reduced to 105 particles per ml for spores and to 5 × 104 particles per ml for poxviruses. The influence on particle detection of incubation time, washing and adsorption procedures was investigated. Conclusions: The reproducibility and sensitivity of the method were acceptable, particularly considering the small sample volume and low particle number applied onto the sample support. Significance and Impact of the Study: Diagnostic negative staining electron microscopy is used for the diagnosis of pathogens in emergency situations because it allows a rapid examination of all particulate matter down to the nanometre scale. This study provides precise detection limit for the method, an important factor for the validation and improvement of the technique.
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Affiliation(s)
- M Laue
- Centre for Biological Safety 4, Robert Koch Institute, Berlin, Germany.
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13
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Töndury B, Kühne A, Kutzner H, Palmedo G, Lautenschlager S, Borelli S. Molecular diagnostics of parapox virus infections. J Dtsch Dermatol Ges 2010; 8:681-4. [PMID: 20497283 DOI: 10.1111/j.1610-0387.2010.07454.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND The diagnosis of parapox virus infections relies primarily on a history of contact with infected animals. The clinical presentation is usually a non-specific necrotic ulcer. The histology may also be non-specific, especially with older lesions. Negative-staining electron microscopy (EM) is a fast and reliable diagnostic tool, but is not widely available. Serological tests and the time-consuming viral culture are also rarely used in Europe. PATIENTS AND METHODS The diagnostic procedure in two patients with ecthyma contagiosum and milker's nodule using polymerase chain reaction specific for orthopox, parapox and Orf virus is explained. Diagnostics included bacterial culture, viral culture, histology and EM. In addition to these, a polymerase chain reaction (PCR) was performed in both cases. RESULTS The patient with ecthyma contagiosum was negative for ortho-, parapox-, and orf-virus on PCR, whereas the patient with milker's nodule had a PCR positive for parapoxvirus. CONCLUSIONS PCR is a simple, fast, and standardized method of diagnosis that can distinguish between the subgroups of parapoxviruses. A diagnosis can be made even in cases of ambiguous history or unspecific clinical presentation. The method is limited by the necessity to sample native material or to use neutrally buffered formalin in case of PCR from paraffin material.
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Affiliation(s)
- Bettina Töndury
- Department of Dermatology, Zurich University Hospital, Zurich, Switzerland
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14
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MacNeil A, Lederman E, Reynolds MG, Ragade NJ, Talken R, Friedman D, Hall W, Shwe T, Li Y, Zhao H, Smith S, Davidson W, Hughes C, Damon IK. Diagnosis of Bovine-Associated Parapoxvirus Infections in Humans: Molecular and Epidemiological Evidence. Zoonoses Public Health 2010; 57:e161-4. [DOI: 10.1111/j.1863-2378.2009.01317.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Abstract
Electron microscopy, considered by some to be an old technique, is still on the forefront of both clinical viral diagnoses and viral ultrastructure and pathogenesis studies. In the diagnostic setting, it is particularly valuable in the surveillance of emerging diseases and potential bioterrorism viruses. In the research arena, modalities such as immunoelectron microscopy, cryo-electron microscopy, and electron tomography have demonstrated how viral structural components fit together, attach to cells, assimilate during replication, and associate with the cellular machinery during replication and egression. These studies provide information for treatment and vaccine strategies.
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Affiliation(s)
- Cynthia S Goldsmith
- Infectious Disease Pathology Branch, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
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16
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MacNeill AL, Moldawer LL, Moyer RW. The role of the cowpox virus crmA gene during intratracheal and intradermal infection of C57BL/6 mice. Virology 2008; 384:151-60. [PMID: 19056101 DOI: 10.1016/j.virol.2008.10.041] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Revised: 09/24/2008] [Accepted: 10/29/2008] [Indexed: 11/28/2022]
Abstract
Intratracheal (i.t.) infection of mice with cowpox virus (CPXV), is lethal at a lower dose than intranasal (i.n.) inoculation. CPXV deleted for cytokine response modifier A (CPXVDeltacrmA) was attenuated compared to CPXV after i.t. inoculation. This attenuation could not be attributed to differences in virus replication, immunomodulators, or cells infiltrating the lungs. Deletion of crmA also caused attenuation during intradermal (i.d.) infection. In contrast to i.t.-inoculated virus, deletion of crmA reduced virus replication at the site of infection. This difference correlated to increased numbers of CD3(+) cells in CPXVDeltacrmA-associated dermal lesions. Thus, crmA is a virulence factor in mice during either pulmonary or dermal cowpox infection; however the influence of crmA is more evident during i.d. inoculation. This suggests that the host immune response differs in the two routes of infection and emphasizes the need to consider the effect of route of infection when examining functions of virulence factors in vivo.
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Affiliation(s)
- A L MacNeill
- Department of Pathobiology, University of Illinois College of Veterinary Medicine, Urbana, IL 61802, USA.
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Huemer HP, Hönlinger B, Höpfl R. A simple restriction fragment PCR approach for discrimination of humanpathogenic Old World animal Orthopoxvirus species. Can J Microbiol 2008; 54:159-62. [PMID: 18388986 DOI: 10.1139/w07-129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There are reliable polymerase chain reaction assays available for exclusion of Variola virus from other poxviruses. However, the discrimination of humanpathogenic animal Orthopoxviridae is more challenging because of the high genomic conservation. Based on the variability of the A36R gene, we describe a simple 20 min PCR assay followed by a 1 h digest with 3 different restriction enzymes. This assay enables rapid discrimination between Cowpox virus and Monkeypox virus and discrimination of the most prevalent members of the Vaccinia virus and Camelpox virus. The test was orthopoxvirus specificand did not react with parapox (Orf) virus. Moreover, the amplified fragments were also well suited for additional genotyping by direct DNA sequencing.
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Affiliation(s)
- Hartwig P Huemer
- Innsbruck Medical University, Department of Hygiene, Microbiology and Social Medicine, Fritz-Pregl-Strasse 3, A-6020 Innsbruck, Austria.
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Kurth A, Nitsche A. Fast and reliable diagnostic methods for the detection of human poxvirus infections. Future Virol 2007. [DOI: 10.2217/17460794.2.5.467] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Although the most prominent poxvirus, Variola virus, was successfully eradicated in the last century, several other poxviruses cause zoonotic infections that, in the early stages, resemble Variola virus infections with varying pathogenicity in humans. Over recent decades, numerous diagnostic methods for the detection of poxviruses have been established. As a result of technical progress and the advancement in molecular techniques, only a small selection of these methods meet the demands of being rapid and reliable. This review briefly introduces human poxviruses, summarizes the methods available, discusses their pros and cons and provides recommendations for a ‘fast and reliable diagnostic approach.
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Affiliation(s)
- Andreas Kurth
- Robert Koch Institute, Center for Biological Safety 1, German Consultant Laboratory for Poxviruses, Nordufer 20, 13353 Berlin, Germany.
| | - Andreas Nitsche
- Robert Koch Institute, Center for Biological Safety 1, German Consultant Laboratory for Poxviruses, Nordufer 20, 13353 Berlin, Germany.
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