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Gujar S, Pol JG, Kumar V, Lizarralde-Guerrero M, Konda P, Kroemer G, Bell JC. Tutorial: design, production and testing of oncolytic viruses for cancer immunotherapy. Nat Protoc 2024; 19:2540-2570. [PMID: 38769145 DOI: 10.1038/s41596-024-00985-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 02/12/2024] [Indexed: 05/22/2024]
Abstract
Oncolytic viruses (OVs) represent a novel class of cancer immunotherapy agents that preferentially infect and kill cancer cells and promote protective antitumor immunity. Furthermore, OVs can be used in combination with established or upcoming immunotherapeutic agents, especially immune checkpoint inhibitors, to efficiently target a wide range of malignancies. The development of OV-based therapy involves three major steps before clinical evaluation: design, production and preclinical testing. OVs can be designed as natural or engineered strains and subsequently selected for their ability to kill a broad spectrum of cancer cells rather than normal, healthy cells. OV selection is further influenced by multiple factors, such as the availability of a specific viral platform, cancer cell permissivity, the need for genetic engineering to render the virus non-pathogenic and/or more effective and logistical considerations around the use of OVs within the laboratory or clinical setting. Selected OVs are then produced and tested for their anticancer potential by using syngeneic, xenograft or humanized preclinical models wherein immunocompromised and immunocompetent setups are used to elucidate their direct oncolytic ability as well as indirect immunotherapeutic potential in vivo. Finally, OVs demonstrating the desired anticancer potential progress toward translation in patients with cancer. This tutorial provides guidelines for the design, production and preclinical testing of OVs, emphasizing considerations specific to OV technology that determine their clinical utility as cancer immunotherapy agents.
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Affiliation(s)
- Shashi Gujar
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
- Beatrice Hunter Cancer Research Institute, Halifax, Nova Scotia, Canada
| | - Jonathan G Pol
- INSERM, U1138, Paris, France
- Equipe 11 labellisée par la Ligue Nationale contre le Cancer, Centre de Recherche des Cordeliers, Paris, France
- Université Paris Cité, Paris, France
- Sorbonne Université, Paris, France
- Metabolomics and Cell Biology Platforms, UMS AMICCa, Gustave Roussy, Villejuif, France
| | - Vishnupriyan Kumar
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
- Beatrice Hunter Cancer Research Institute, Halifax, Nova Scotia, Canada
| | - Manuela Lizarralde-Guerrero
- INSERM, U1138, Paris, France
- Equipe 11 labellisée par la Ligue Nationale contre le Cancer, Centre de Recherche des Cordeliers, Paris, France
- Université Paris Cité, Paris, France
- Sorbonne Université, Paris, France
- Metabolomics and Cell Biology Platforms, UMS AMICCa, Gustave Roussy, Villejuif, France
- Ecole Normale Supérieure de Lyon, Lyon, France
| | - Prathyusha Konda
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Harvard Medical School, Harvard University, Boston, MA, USA
| | - Guido Kroemer
- INSERM, U1138, Paris, France.
- Equipe 11 labellisée par la Ligue Nationale contre le Cancer, Centre de Recherche des Cordeliers, Paris, France.
- Université Paris Cité, Paris, France.
- Sorbonne Université, Paris, France.
- Metabolomics and Cell Biology Platforms, UMS AMICCa, Gustave Roussy, Villejuif, France.
- Institut Universitaire de France, Paris, France.
- Institut du Cancer Paris CARPEM, Hôpital Européen Georges Pompidou, AP-HP, Paris, France.
| | - John C Bell
- Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
- Department of Biochemistry, Microbiology & Immunology, University of Ottawa, Ottawa, Ontario, Canada.
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.
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Rowan NJ. Current decontamination challenges and potentially complementary solutions to safeguard the vulnerable seafood industry from recalcitrant human norovirus in live shellfish: Quo Vadis? THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 874:162380. [PMID: 36841407 DOI: 10.1016/j.scitotenv.2023.162380] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/16/2023] [Accepted: 02/17/2023] [Indexed: 06/18/2023]
Abstract
Safeguarding the seafood industry is important given its contribution to supporting our growing global population. However, shellfish are filter feeders that bioaccumulate microbial contaminants in their tissue from wastewater discharged into the same coastal growing environments leading to significant human disease outbreaks unless appropriately mitigated. Removal or inactivation of enteric viruses is very challenging particularly as human norovirus (hNoV) binds to specific histo-blood ligands in live oyster tissue that are consumed raw or lightly cooked. The regulatory framework that sets out use of clean seawater and UV disinfection is appropriate for bacterial decontamination at the post-harvest land-based depuration (cleaning) stage. However, additional non-thermal technologies are required to eliminate hNoV in live shellfish (particularly oysters) where published genomic studies report that low-pressure UV has limited effectiveness in inactivating hNoV. The use of the standard genomic detection method (ISO 15, 216-1:2017) is not appropriate for assessing the loss of infectious hNoV in treated live shellfish. The use of surrogate viral infectivity methods appear to offer some insight into the loss of hNoV infectiousness in live shellfish during decontamination. This paper reviews the use of existing and potentially other combinational treatment approaches to enhance the removal or inactivation of enteric viruses in live shellfish. The use of alternative and complementary novel diagnostic approaches to discern viable hNoV are discussed. The effectiveness and virological safety of new affordable hNoV intervention(s) require testing and validating at commercial shellfish production in conjunction with laboratory-based research. Appropriate risk management planning should encompass key stakeholders including local government and the wastewater industry. Gaining a mechanistic understanding of the relationship between hNoV response at molecular and structural levels in individually treated oysters as a unit will inform predictive modeling and appropriate treatment technologies. Global warming of coastal growing environments may introduce additional contaminant challenges (such as invasive species); thus, underscoring need to develop real-time ecosystem monitoring of growing environments to alert shellfish producers to appropriately mitigate these threats.
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Affiliation(s)
- Neil J Rowan
- Centre for Sustainable Disinfection and Sterilization, Bioscience Research Institute, Technological University of the Shannon Midlands Midwest, Athlone Campus, Ireland.
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Vermisoglou E, Panáček D, Jayaramulu K, Pykal M, Frébort I, Kolář M, Hajdúch M, Zbořil R, Otyepka M. Human virus detection with graphene-based materials. Biosens Bioelectron 2020; 166:112436. [PMID: 32750677 PMCID: PMC7375321 DOI: 10.1016/j.bios.2020.112436] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/22/2020] [Accepted: 07/07/2020] [Indexed: 02/06/2023]
Abstract
Our recent experience of the COVID-19 pandemic has highlighted the importance of easy-to-use, quick, cheap, sensitive and selective detection of virus pathogens for the efficient monitoring and treatment of virus diseases. Early detection of viruses provides essential information about possible efficient and targeted treatments, prolongs the therapeutic window and hence reduces morbidity. Graphene is a lightweight, chemically stable and conductive material that can be successfully utilized for the detection of various virus strains. The sensitivity and selectivity of graphene can be enhanced by its functionalization or combination with other materials. Introducing suitable functional groups and/or counterparts in the hybrid structure enables tuning of the optical and electrical properties, which is particularly attractive for rapid and easy-to-use virus detection. In this review, we cover all the different types of graphene-based sensors available for virus detection, including, e.g., photoluminescence and colorimetric sensors, and surface plasmon resonance biosensors. Various strategies of electrochemical detection of viruses based on, e.g., DNA hybridization or antigen-antibody interactions, are also discussed. We summarize the current state-of-the-art applications of graphene-based systems for sensing a variety of viruses, e.g., SARS-CoV-2, influenza, dengue fever, hepatitis C virus, HIV, rotavirus and Zika virus. General principles, mechanisms of action, advantages and drawbacks are presented to provide useful information for the further development and construction of advanced virus biosensors. We highlight that the unique and tunable physicochemical properties of graphene-based nanomaterials make them ideal candidates for engineering and miniaturization of biosensors.
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Affiliation(s)
- Eleni Vermisoglou
- Regional Centre of Advanced Technologies and Materials (RCPTM), Faculty of Science, Palacký University Olomouc, Czech Republic
| | - David Panáček
- Regional Centre of Advanced Technologies and Materials (RCPTM), Faculty of Science, Palacký University Olomouc, Czech Republic; Department of Physical Chemistry, Faculty of Science, Palacký University Olomouc, Czech Republic
| | - Kolleboyina Jayaramulu
- Regional Centre of Advanced Technologies and Materials (RCPTM), Faculty of Science, Palacký University Olomouc, Czech Republic; Department of Chemistry, Indian Institute of Technology Jammu, Jammu & Kashmir, 181221, India
| | - Martin Pykal
- Regional Centre of Advanced Technologies and Materials (RCPTM), Faculty of Science, Palacký University Olomouc, Czech Republic
| | - Ivo Frébort
- Centre of the Region Haná (CRH), Faculty of Science, Palacký University Olomouc, Czech Republic
| | - Milan Kolář
- Department of Microbiology, Faculty of Medicine and Dentistry, Palacký University Olomouc, Czech Republic
| | - Marián Hajdúch
- Institute of Molecular and Translational Medicine (UMTM), Faculty of Medicine and Dentistry, Palacký University Olomouc, Czech Republic
| | - Radek Zbořil
- Regional Centre of Advanced Technologies and Materials (RCPTM), Faculty of Science, Palacký University Olomouc, Czech Republic
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials (RCPTM), Faculty of Science, Palacký University Olomouc, Czech Republic.
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Guliy OI, Zaitsev BD, Larionova OS, Borodina IA. Virus Detection Methods and Biosensor Technologies. Biophysics (Nagoya-shi) 2020. [DOI: 10.1134/s0006350919060095] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Gast M, Kühner S, Sobek H, Walther P, Mizaikoff B. Enhanced Selectivity by Passivation: Molecular Imprints for Viruses with Exceptional Binding Properties. Anal Chem 2018; 90:5576-5585. [DOI: 10.1021/acs.analchem.7b05148] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
| | - Stefanie Kühner
- Labor Dr. Merk & Kollegen GmbH, Beim Braunland 1, 88414 Ochsenhausen, Germany
| | - Harald Sobek
- Labor Dr. Merk & Kollegen GmbH, Beim Braunland 1, 88414 Ochsenhausen, Germany
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Khalil JYB, Langlois T, Andreani J, Sorraing JM, Raoult D, Camoin L, La Scola B. Flow Cytometry Sorting to Separate Viable Giant Viruses from Amoeba Co-culture Supernatants. Front Cell Infect Microbiol 2017; 6:202. [PMID: 28111619 PMCID: PMC5216029 DOI: 10.3389/fcimb.2016.00202] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 12/15/2016] [Indexed: 12/03/2022] Open
Abstract
Flow cytometry has contributed to virology but has faced many drawbacks concerning detection limits, due to the small size of viral particles. Nonetheless, giant viruses changed many concepts in the world of viruses, as a result of their size and hence opened up the possibility of using flow cytometry to study them. Recently, we developed a high throughput isolation of viruses using flow cytometry and protozoa co-culture. Consequently, isolating a viral mixture in the same sample became more common. Nevertheless, when one virus multiplies faster than others in the mixture, it is impossible to obtain a pure culture of the minority population. Here, we describe a robust sorting system, which can separate viable giant virus mixtures from supernatants. We tested three flow cytometry sorters by sorting artificial mixtures. Purity control was assessed by electron microscopy and molecular biology. As proof of concept, we applied the sorting system to a co-culture supernatant taken from a sample containing a viral mixture that we couldn't separate using end point dilution. In addition to isolating the quick-growing Mimivirus, we sorted and re-cultured a new, slow-growing virus, which we named “Cedratvirus.” The sorting assay presented in this paper is a powerful and versatile tool for separating viral populations from amoeba co-cultures and adding value to the new field of flow virometry.
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Affiliation(s)
- Jacques Y B Khalil
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UM63 Centre national de la Recherche Scientifique 7278 IRD 198 Institut National de la Santé et de la Recherche Médicale U1095, Facultés de Médecine et de PharmacieMarseille, France; Institut Hospitalo-Universitaire Méditerranée Infection, Pôle des Maladies Infectieuses et Tropicales Clinique et Biologique, Fédération de Bactériologie-Hygiène-Virologie, Centre Hospitalo-Universitaire Timone, Assistance Publique-Hôpitaux de MarseilleMarseille, France
| | - Thierry Langlois
- Becton Dickinson (Life Sciences-Biosciences) 94523 Rungis Cedex, France
| | - Julien Andreani
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UM63 Centre national de la Recherche Scientifique 7278 IRD 198 Institut National de la Santé et de la Recherche Médicale U1095, Facultés de Médecine et de PharmacieMarseille, France; Institut Hospitalo-Universitaire Méditerranée Infection, Pôle des Maladies Infectieuses et Tropicales Clinique et Biologique, Fédération de Bactériologie-Hygiène-Virologie, Centre Hospitalo-Universitaire Timone, Assistance Publique-Hôpitaux de MarseilleMarseille, France
| | | | - Didier Raoult
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UM63 Centre national de la Recherche Scientifique 7278 IRD 198 Institut National de la Santé et de la Recherche Médicale U1095, Facultés de Médecine et de PharmacieMarseille, France; Institut Hospitalo-Universitaire Méditerranée Infection, Pôle des Maladies Infectieuses et Tropicales Clinique et Biologique, Fédération de Bactériologie-Hygiène-Virologie, Centre Hospitalo-Universitaire Timone, Assistance Publique-Hôpitaux de MarseilleMarseille, France
| | - Laurence Camoin
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UM63 Centre national de la Recherche Scientifique 7278 IRD 198 Institut National de la Santé et de la Recherche Médicale U1095, Facultés de Médecine et de PharmacieMarseille, France; Institut Hospitalo-Universitaire Méditerranée Infection, Pôle des Maladies Infectieuses et Tropicales Clinique et Biologique, Fédération de Bactériologie-Hygiène-Virologie, Centre Hospitalo-Universitaire Timone, Assistance Publique-Hôpitaux de MarseilleMarseille, France
| | - Bernard La Scola
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UM63 Centre national de la Recherche Scientifique 7278 IRD 198 Institut National de la Santé et de la Recherche Médicale U1095, Facultés de Médecine et de PharmacieMarseille, France; Institut Hospitalo-Universitaire Méditerranée Infection, Pôle des Maladies Infectieuses et Tropicales Clinique et Biologique, Fédération de Bactériologie-Hygiène-Virologie, Centre Hospitalo-Universitaire Timone, Assistance Publique-Hôpitaux de MarseilleMarseille, France
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Garcia V, Krishnan R, Davis C, Batenchuk C, Le Boeuf F, Abdelbary H, Diallo JS. High-throughput titration of luciferase-expressing recombinant viruses. J Vis Exp 2014:51890. [PMID: 25285536 PMCID: PMC4828131 DOI: 10.3791/51890] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Standard plaque assays to determine infectious viral titers can be time consuming, are not amenable to a high volume of samples, and cannot be done with viruses that do not form plaques. As an alternative to plaque assays, we have developed a high-throughput titration method that allows for the simultaneous titration of a high volume of samples in a single day. This approach involves infection of the samples with a Firefly luciferase tagged virus, transfer of the infected samples onto an appropriate permissive cell line, subsequent addition of luciferin, reading of plates in order to obtain luminescence readings, and finally the conversion from luminescence to viral titers. The assessment of cytotoxicity using a metabolic viability dye can be easily incorporated in the workflow in parallel and provide valuable information in the context of a drug screen. This technique provides a reliable, high-throughput method to determine viral titers as an alternative to a standard plaque assay.
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Affiliation(s)
- Vanessa Garcia
- Center for Innovative Cancer Research, Ottawa Hospital Research Institute; Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa
| | - Ramya Krishnan
- Center for Innovative Cancer Research, Ottawa Hospital Research Institute; Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa
| | - Colin Davis
- Center for Innovative Cancer Research, Ottawa Hospital Research Institute; Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa
| | - Cory Batenchuk
- Center for Innovative Cancer Research, Ottawa Hospital Research Institute; Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa
| | - Fabrice Le Boeuf
- Center for Innovative Cancer Research, Ottawa Hospital Research Institute; Faculty of Medicine, University of Ottawa
| | - Hesham Abdelbary
- Center for Innovative Cancer Research, Ottawa Hospital Research Institute; Faculty of Medicine, University of Ottawa
| | - Jean-Simon Diallo
- Center for Innovative Cancer Research, Ottawa Hospital Research Institute; Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa;
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Salma M, Rousseaux S, Sequeira-Le Grand A, Alexandre H. Cytofluorometric detection of wine lactic acid bacteria: application of malolactic fermentation to the monitoring. ACTA ACUST UNITED AC 2013; 40:63-73. [DOI: 10.1007/s10295-012-1200-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 09/15/2012] [Indexed: 11/29/2022]
Abstract
Abstract
In this study we report for the first time a rapid, efficient and cost-effective method for the enumeration of lactic acid bacteria (LAB) in wine. Indeed, up to now, detection of LAB in wine, especially red wine, was not possible. Wines contain debris that cannot be separated from bacteria using flow cytometry (FCM). Furthermore, the dyes tested in previous reports did not allow an efficient staining of bacteria. Using FCM and a combination of BOX/PI dyes, we were able to count bacteria in wines. The study was performed in wine inoculated with Oenococcus oeni (106 CFU ml−1) stained with either FDA or BOX/PI and analyzed by FCM during the malolactic fermentation (MLF). The analysis show a strong correlation between the numbers of BOX/PI-stained cells determined by FCM and the cell numbers determined by plate counts (red wine: R2 ≥ 0.97, white wine R2 ≥ 0.965). On the other hand, we found that the enumeration of O. oeni labeled with FDA was only possible in white wine (R2 ≥ 0.97). Viable yeast and LAB populations can be rapidly discriminated and quantified in simultaneous malolactic-alcoholic wine fermentations using BOX/PI and scatter parameters in a one single measurement. This rapid procedure is therefore a suitable method for monitoring O. oeni populations during winemaking, offers a detection limit of <104 CFU ml−1 and can be considered a useful method for investigating the dynamics of microbial growth in wine and applied for microbiological quality control in wineries.
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Affiliation(s)
- Mohammad Salma
- grid.5613.1 0000000122989313 UMR 02102 PAM Université de Bourgogne-AgroSup Dijon Laboratoire VALMIS Institut Universitaire de la Vigne et du Vin Jules Guyot Université de Bourgogne 21078 Dijon Cedex France
| | - Sandrine Rousseaux
- grid.5613.1 0000000122989313 UMR 02102 PAM Université de Bourgogne-AgroSup Dijon Laboratoire VALMIS Institut Universitaire de la Vigne et du Vin Jules Guyot Université de Bourgogne 21078 Dijon Cedex France
| | - Anabelle Sequeira-Le Grand
- grid.5613.1 0000000122989313 Plateforme de Cytométrie, Structure Fédérative de Recherche Santé STIC, Fac. Médecine Université de Bourgogne 7, Bd Jeanne D’Arc 21000 Dijon France
| | - Hervé Alexandre
- grid.5613.1 0000000122989313 UMR 02102 PAM Université de Bourgogne-AgroSup Dijon Laboratoire VALMIS Institut Universitaire de la Vigne et du Vin Jules Guyot Université de Bourgogne 21078 Dijon Cedex France
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Wozniak-Kosek A, Brydak LB. Flow cytometry in the diagnosis of influenza. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 788:65-70. [PMID: 23835960 DOI: 10.1007/978-94-007-6627-3_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Flow cytometry is used in the analysis of the multi-parameter optical properties of individual particles such as eukaryotic cells, prokaryotic cells, and viruses in the flow system. Virions, or complexes consisting of virus particles attached to the specific antibody in suspension are individually arranged in a linear stream, which flows through the detection device. The parameters measured by the flow cytometer include the volume of the particles or cells, the morphological complexity, the presence of pigments, RNA content, virion surface markers, and enzymatic activity. It is possible to collect two morphological parameters and one or more signals of the fluorescence of a single particle. Multi-parameter analysis provides for the definition a population of cells based on their phenotype. Flow cytometry is characterized by the automatic determination of the value of the parameter set for a large number of individual particles or cells in the course of each measurement. For example, 100,000 or more particles such as virus, bacteria, or fungal spores are analyzed one after another typically over a period of 1 min. The limit of detection in such studies is 100 fluorescing particles per cell. Theoretically, in the case of the influenza virus, this will be one copy of the virion combined in a complex with specific antibodies and with a built-in fluorescent label.
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Affiliation(s)
- Agnieszka Wozniak-Kosek
- Department of Influenza Research, National Influenza Center, National Institute of Public Health-National Institute of Hygiene, 24 Chocimska St., 00-791, Warsaw, Poland,
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Affiliation(s)
- Raoul K. Boughton
- Avian Ecology, Archbold Biological Station, 123 Main Drive, Venus, Florida, USA
| | - Gerrit Joop
- Institute of Integrative Biology,
Experimental Ecology, ETH Zürich, CH‐8092 Zürich, Switzerland
| | - Sophie A.O. Armitage
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, D‐48149 Münster, Germany
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Flow Cytometry: A Multipurpose Technology for a Wide Spectrum of Global Biosecurity Applications. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.jala.2009.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Flow cytometry, and its offspring-flow sorting, are extremely useful technologies for biosecurity and public health studies related to infectious disease. Applications range from environmental surveillance of pathogens to diagnosis and the development of vaccines and therapeutics for prevention and control of infectious diseases. Flow cytometers have been developed for laboratory analysis and field deployment. The current state of the art could enjoy more widespread use if instruments and data analysis were made simpler and had more automated functions, and if technology was modified to reduce biosafety concerns related to analysis and sorting of infectious organisms. The full spectrum of possible applications of flow cytometry technology to global biosecurity challenges has not yet been realized.
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Sun Z, Ceng X, Mao Z, Wang J, Liu Q, Ji Y, Ma Y, Qi Y, He R, Ruan Q. Diagnostic value of HCMV pp65 antigen detection by FCA for symptomatic and asymptomatic infection: compared to quantification of HCMV DNA and detection of IgM antibody in infants. Med Microbiol Immunol 2009; 198:107-12. [PMID: 19308446 DOI: 10.1007/s00430-009-0112-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Indexed: 12/27/2022]
Abstract
Human cytomegalovirus (HCMV) can cause symptomatic or asymptomatic infection in infants. One hundred and twenty-six infants were assessed clinically for disease in infantile period. Eighty of them were classified as symptomatic infection on the basis of physical, instrumental, and laboratory findings, 5 were demonstrated by following up to have later developed HCMV disease, and the other 41 infants were classified as asymptomatic infection. HCMV DNA was positive in all urine samples of the symptomatic infants detected by quantitative polymerase chain reaction. HCMV-IgM antibody detected by chemiluminescent immunoassay (CLIA) was positive in 62 of the 85 symptomatic infants, but was negative in all of the samples of asymptomatic infants. HCMV pp65 antigen detected by flow cytometry assay (FCA) was positive in 77 of the 85 symptomatic infants and in none of the asymptomatic infants. The coincidence to symptom of HCMV pp65 antigen detection was higher than those of HCMV DNA and HCMV-IgM antibody detection. The sensitivity, specificity, positive prognostic value and the negative prognostic value of HCMV pp65 antigen detection for diagnosis of HCMV infection was 90.6, 100, 100 and 83.7%, respectively. We concluded that detection of pp65 antigen by FCA is more sensitive for diagnosis of HCMV infection than detection of HCMV-IgM antibody and is better than HCMV DNA quantification for distinguishing the symptomatic and asymptomatic HCMV infection in infants.
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Affiliation(s)
- Zhengrong Sun
- Virus Laboratory, The Affiliated Shengjing Hospital, China Medical University, 110004 Shenyang, Liaoning, China
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Chen ZY, Liu H, Li ZQ, Zhang QY. Development and characterization of monoclonal antibodies to spring viraemia of carp virus. Vet Immunol Immunopathol 2008; 123:266-76. [PMID: 18378003 DOI: 10.1016/j.vetimm.2008.02.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2007] [Revised: 01/28/2008] [Accepted: 02/08/2008] [Indexed: 11/27/2022]
Abstract
Five monoclonal antibodies (mAbs) against spring viraemia of carp (SVCV0504, isolated from common carp in China) were produced from mice immunized with purified virus preparations. The virion of SVCV contains five structural proteins, representing the nucleoprotein (N), phosphoprotein (P), matrix protein (M), glycoprotein (G) and RNA-dependent RNA polymerase (L). Western blotting analysis revealed that three mAbs (1H5, 1E10, and 1H7) recognized specifically to a single protein of 47kDa (N), the mAb 3G4 reacted with two SVCV0504 proteins of 69kDa (G) and 47kDa (N), while the mAb 1A9 reacted with three SVCV0504 proteins of 69kDa (G), 50kDa (P), and 47kDa (N). By indirect ELISA, two mAbs (1H5 and 1H7) showed cross-reactivity with pike fry rhabdovirus (PFRV), but no cross-reactions with the Siniperca chuatsi rhabdovirus (SCRV), Scophthalmus maximus rhabdovirus (SMRV), Paralichthys olivaceus rhabdovirus (PoRV) were demonstrated with the five mAbs. Indirect immunofluorescence showed intense fluorescence in the cytoplasm of the SVCV0504-infected epithelioma papulosum cyprini (EPC) cells in areas corresponding to the location of granular structures. The sucrose gradient-purified SVCV0504 particles could be detected successfully by these mAbs using immunodot blotting. mAb 1A9 could completely neutralize 100 TCID(50) (50% tissue culture infective dose) of SVCV0504 at a dilution of 1:8. This is the first report of development of the neutralizing mAbs against SVCV. The mAb 1A9 was analyzed further and could be used to successfully detect viral antigens in the infected-EPC cell cultures or in cryosections from experimentally infected crucian carp (Carassius auratus) by immunohistochemistry assay. Furthermore, a flow cytometry procedure for the detection and quantification of cytoplasmic SVCV0504 in cell cultures was developed with mAb 1A9. At 28h after inoculation with the virus (0.01PFU/cell), 10.12% of infected cells could be distinguished from the uninfected cells. These mAbs will be useful in diagnostic test development and pathogenesis studies for fish rhabdovirus.
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Affiliation(s)
- Zhong-Yuan Chen
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Wuhan 430072, China
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14
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Tiwari A, Patnayak DP, Chander Y, Goyal SM. Permissibility of different cell types for the growth of avian metapneumovirus. J Virol Methods 2006; 138:80-4. [PMID: 16930732 DOI: 10.1016/j.jviromet.2006.07.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Revised: 07/17/2006] [Accepted: 07/19/2006] [Indexed: 11/29/2022]
Abstract
Vero cells are commonly used for the growth of avian metapneumovirus subtype C (aMPV-C). This study was conducted to evaluate 17 different cell types for the growth of a Minnesota strain of aMPV-C. The virus was inoculated into these cell types and virus growth was monitored by the development of cytopathic effects (cpe) and immunofluorescence. Virus growth was obtained in 6 of 17 cell types tested with the highest virus titers observed in BGM and DF-1 cells. The flow cytometric analysis of cells at 72 h post inoculation found the highest number of infected cells in BGM cells followed by QT-35 cells. At 48 h post inoculation, DF-1 and BGM cells showed the highest number of infected cells. These results suggest that BGM, QT-35, and DF-1 cells can be used for high titer propagation of aMPV-C.
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Affiliation(s)
- A Tiwari
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, 1333 Gortner Avenue, St. Paul, MN 55108, USA
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15
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Zhou GZ, Li ZQ, Zhang QY. Characterization and Application of Monoclonal Antibodies against Turbot (Scophthalmus maximus) Rhabdovirus. Viral Immunol 2006; 19:637-45. [PMID: 17201659 DOI: 10.1089/vim.2006.19.637] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Five monoclonal antibodies (mAbs), 1G8, 1H9, 2D2, 2D3, and 2F5, against Scophthalmus maximus rhabdovirus (SMRV) were prepared. Characterization of the mAbs included indirect enzyme-linked immunosorbent assay, isotyping, viral inhibition assay, immunofluorescence staining of virus-infected cell cultures, and Western blot analysis. Isotyping revealed that 1G8 and 1H9 were of the IgG2b subclass and that the other three were IgM. 2D2, 2D3, and 2F5 partially inhibited SMRV infection in epithelioma papulosum cyprinid (EPC) cell culture. Western blotting showed that all five mAbs could react with two SMRV proteins with molecular masses of approximately 30 kDa (P) and 26 kDa (M). These two proteins were localized within the cytoplasm of SMRV-infected EPC cells by immunofluorescence assay. Also, progressive foci of viral replication in cell cultures were monitored from 6 to 24 h, using mAb 2D3 as the primary antibody. A flow cytometry procedure was used to detect and quantify SMRV-infected (0.01 PFU/cell) EPC cells with mAb 2D3, and 10.8% of cells could be distinguished as infected 36 h postinfection. Moreover, mAb 2D3 was successfully applied for the detection of viral antigen in cryosections from flounder tissues by immunohistochemistry tests.
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Affiliation(s)
- Guang-Zhou Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Wuhan, China
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16
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Saez-Lopez C, Ngambe-Tourere E, Rosenzwajg M, Petit JC, Nicolas JC, Gozlan J. Immediate-early antigen expression and modulation of apoptosis after in vitro infection of polymorphonuclear leukocytes by human cytomegalovirus. Microbes Infect 2005; 7:1139-49. [PMID: 15908252 DOI: 10.1016/j.micinf.2005.03.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2004] [Revised: 03/18/2005] [Accepted: 03/21/2005] [Indexed: 10/25/2022]
Abstract
Polymorphonuclear leukocytes (PMNL) are a major carrier of human cytomegalovirus (CMV) in viremic immunodepressed patients. We transmitted infectious virions and viral components to PMNL by coculturing these cells with infected human embryonic lung fibroblasts (HELF) or human umbilical vein endothelial cells (HUVEC). Quantitative time-course analysis of viral DNA and protein expression in PMNL, after functional separation from infected donor cells, indicated the initiation of viral cycling, with immediate-early protein expression. No viral replication or early or late gene expression was observed, but infected PMNL were able to infect naive fibroblasts more than 48 h after the end of co-culture. PMNL apoptosis was significantly delayed during co-culture with infected or uninfected HUVEC, and this phenomenon did not require contact between the two cell populations. The increased production of IL-8 in the same culture conditions that protect PMNL from apoptosis, associated with the reversion of this protection by inhibiting or depleting this factor in the culture media, targets this cytokine as a likely candidate for this protective effect. These data suggest that PMNL play a key role in virus dissemination in vivo, through their interactions with infected endothelial cells.
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Affiliation(s)
- Corinne Saez-Lopez
- Laboratoire de Bactériologie-Virologie, hôpital Saint-Antoine, 184, rue du Faubourg Saint Antoine, 75012 Paris, France
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17
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Qin QW, Gin KYH, Lee LY, Gedaria AI, Zhang S. Development of a flow cytometry based method for rapid and sensitive detection of a novel marine fish iridovirus in cell culture. J Virol Methods 2005; 125:49-54. [PMID: 15737416 DOI: 10.1016/j.jviromet.2004.12.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2004] [Revised: 12/13/2004] [Accepted: 12/16/2004] [Indexed: 11/19/2022]
Abstract
A sensitive and accurate flow cytometry (FCM) based method has been developed to detect and quantitate a novel marine fish iridovirus (Singapore grouper iridovirus, SGIV) after amplification in cell cultures. Confluent grouper cell (GP) monolayers were infected with SGIV. When advanced cytopathic effect (CPE) appeared, the cell cultures were fixed and permeabilized, and then reacted with monoclonal antibodies specific against SGIV, followed by a second antibody conjugated with FITC (anti-mouse IgG-FITC). A Coulter EPICS Elite ESP flow cytometer was used to directly detect and analyze the percentage of virus-infected cells. Three fixation and permeabilization methods were evaluated. The kinetics of the virus infection process was determined. The FCM procedure enables large amounts of cells to be screened rapidly for infectivity, and it can also detect low levels of virus infection. As early as 8 h after inoculation with the virus, 0.34% of infected cells were detected in cell culture. The maximum level of infection was obtained at 72 h. The efficiency and reliability of the FCM procedure were compared with those of the standard methods of immunofluorescence microscopy and PCR.
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Affiliation(s)
- Qi Wei Qin
- State Key Laboratory for Biocontrol, College of Life Science, Zhongshan University, 135 West Xingang Road, Guangzhou 510275, PR China.
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18
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Abstract
A simple algorithm is presented for quantitative analysis of simultaneous events on a dual-channel flow cytometer designed specifically for virus counting. The algorithm, which is based on matrix analysis of burst lag times, was evaluated using baculovirus samples that had previously been quantified by the plaque titer method. The results indicated statistical reliability for the algorithm, with three of six samples yielding the same value, within error, for viruses per unit volume as the plaque titer. The other three samples yielded values within a factor approximately 2, which was deemed acceptable given the limitations of the plaque titer method.
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Affiliation(s)
- Carrie L Stoffel
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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19
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Stoffel CL, Kathy RF, Rowlen KL. Design and characterization of a compact dual channel virus counter. Cytometry A 2005; 65:140-7. [PMID: 15830378 DOI: 10.1002/cyto.a.20145] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Although there is a growing need in the field of biotechnology to rapidly and accurately quantify viruses, time-consuming techniques such as the plaque titer method remain the "gold standard." Flow cytometric methods for virus quantification offer the advantages of rapid analysis and statistical treatment. The technique presented in this work represents the first demonstration of a flow cytometric determination of a viral count that is directly related to the count obtained by plaque titer. METHODS A flow cytometric instrument for rapid quantification of virus particles was designed, constructed, and thoroughly characterized. A two-color method, which involved staining the viral genome and the protein coat for baculoviruses, was developed in addition to an algorithm to identify simultaneous events on the DNA and protein channels. RESULTS The instrument was fully characterized, which included analysis of the data acquisition rate, sampling time, flow rate, detection efficiency, linear dynamic range, channel cross-talk, and the limit of detection. Baculovirus samples were analyzed and the results were compared with concentrations obtained by a one-channel flow cytometer and plaque assay. CONCLUSIONS The dual channel virus counter yields a representative value for the concentration of active viruses in an unpurified sample when compared with plaque assay and a one-channel flow cytometer. The technique is rapid (within minutes), requires only minimal sample preparation and minimum sample size (approximately 100 microl).
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Affiliation(s)
- Carrie L Stoffel
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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20
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Miura T, Yokoyama H, Minegishi N, Sasaki T, Kaku M, Harigae H. Flow cytometry of GATA transcription factors. ACTA ACUST UNITED AC 2003; 56:1-7. [PMID: 14582131 DOI: 10.1002/cyto.b.10047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Although GATA-1 and GATA-2 have been shown to play an important role in hematopoiesis, the expression levels of these GATA proteins in the targeted cell population of clinical samples have not been studied. We applied flow cytometry (FCM) to examine the expression levels of these GATA proteins in the selected subpopulation in heterogeneous blood cells. METHODS Cells were treated with a fixing solution and methanol followed by staining with specific antibodies to GATA proteins in a permeabilizing solution. Immunofluorescence microscopy and Northern blot analysis using GATA-1 and GATA-2 transfected cell lines and various leukemic cell lines were used to confirm the specificity of this method. Subsequently, the method was applied in two-parameter studies combining GATA expression with surface marker expression in clinical samples. RESULTS The positive signals were specifically detected in transfected cells and leukemic cell lines by FCM in agreement with the results of Northern blot and immunofluorescence microscopy. The expression of these GATA factors in the targeted cell population was easily detectable by gating with lineage-specific cell surface markers. When the expression of these GATA proteins was examined in glycophorin A-positive cells in clinical samples, the level of GATA-1 was markedly different among the samples. CONCLUSIONS This detection system is useful to evaluate the relative expression level of each GATA protein in the targeted cell population among heterogeneous cells, and the results suggest an aberrant expression of GATA factors in hematological diseases.
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Affiliation(s)
- Toshihiko Miura
- Department of Molecular Diagnostics, Tohoku University School of Medicine, Sendai, Japan.
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21
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Bordignon J, Pires Ferreira SC, Medeiros Caporale GM, Carrieri ML, Kotait I, Lima HC, Zanetti CR. Flow cytometry assay for intracellular rabies virus detection. J Virol Methods 2002; 105:181-6. [PMID: 12176155 DOI: 10.1016/s0166-0934(02)00064-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Following previous studies reporting microbiological diagnosis by flow cytometry, the possibility of using this method was examined to monitor infection of susceptible cell lines by a fixed rabies virus strain (Pasteur Virus strain-PV) or a wild rabies virus strain (WRS). Suspensions of BHK-21 and C6 cells were infected with viruses and a time course of virus infection was established. Sequentially, at several time points, infected and control uninfected cells were fixed, permeabilized, and stained with a rabies virus-specific antibody conjugate. This was achieved by resuspending cells in a solution containing p-formaldehyde in FACS lysis fluid, which allowed the detection of intracellular virus with flourescein-coupled antibodies by flow cytometry. A Becton Dickinson FACSCalibur flow cytometer was used to analyze the percentage of cells infected and the kinetics of the infection process was determined. As early as 12 h after inoculation with both rabies virus strains, significant levels (P<0.01) of infection (from 4.7 to 7.1%) were detected by flow cytometry. The maximum level of infection was obtained at 48 h in C6 cells (88%) with both viruses. The advantages of this method for examination of intracellular virus infection are discussed.
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Affiliation(s)
- Juliano Bordignon
- Laboratory of Immunology, Department of Microbiology and Parasitology at Federal University of Santa Catarina, SC Florianópolis, 88040-900 Brazil
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22
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Ferris MM, Stoffel CL, Maurer TT, Rowlen KL. Quantitative intercomparison of transmission electron microscopy, flow cytometry, and epifluorescence microscopy for nanometric particle analysis. Anal Biochem 2002; 304:249-56. [PMID: 12009703 DOI: 10.1006/abio.2002.5616] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nanometric biological particles such as viruses have received increased attention in a wide range of scientific fields. Evaluation of viral contributions to environmental processes and the use of viruses in medical applications such as gene therapy require viruses to be routinely and accurately enumerated. There are a variety of existing techniques for counting viruses, namely, plaque assays, transmission electron microscopy (TEM), epifluorescence microscopy (EFM), and flow cytometry (FCM); each has advantages and disadvantages. While there have been attempts to intercompare some of these techniques to determine the most effective means to count viruses, no previous study used a technique-independent standard for quantitative comparison of collection efficiency, accuracy, and precision. In this work, polystyrene nanospheres were used as standards for the intercomparison of performance characteristics for TEM, EFM, FCM, as well as a custom-built flow cytometer (the Single Nanometric Particle Enumerator, SNaPE). EFM and SNaPE exhibited the highest degree of accuracy and precision, with particle concentrations deviating < or =5% from true and relative errors less than half that of TEM, EFM and SNaPE are also significantly more time and cost efficient than TEM.
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Affiliation(s)
- Matthew M Ferris
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
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23
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Bordignon J, Comin F, Ferreira SCP, Caporale GMM, Lima Filho JHC, Zanetti CR. Calculating rabies virus neutralizing antibodies titres by flow cytometry. Rev Inst Med Trop Sao Paulo 2002; 44:151-4. [PMID: 12163908 DOI: 10.1590/s0036-46652002000300007] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The determination of the rabies neutralizing antibody (VNA) response after immunization against rabies is an acceptable index of the efficacy of a vaccine and a successful treatment. Several tests have been developed in attempt to improve the assessment of VNA, from mice inoculation to cell-culture fluorescence inhibition tests. All of them, however, present special difficulties in terms of reading or accuracy. The present study describes a neutralization test performed in cell-culture appraised by flow cytometry (FC). Serial dilutions of the serum samples were mixed in vitro with rabies virus before the addition of BHK-21 cells. After 24h-incubation, cells were released by trypsin treatment, fixed and permeabilized with a p-formaldehyde solution and stained with a rabies virus nucleocapsid protein-specific antibody conjugate. The percentage of virus infection inhibition caused by specific antibodies present in the serum were evaluated in a Beckton Dickinson FACSCalibur flow cytometer. A correlation curve between the IU/ml content and the percentage of infective inhibition was built with a reference serum and the VNA titers of serum samples were obtained by extrapolation. Titers obtained by FC and standard test showed an effective pairing results (p < 0.01), with a correlation coefficient (r) = 0.7. These results permit to envisage the FC as a suitable technique to evaluate VNA in sera from immunized animals and likely in human serum samples. Nevertheless, new studies comparing FC to gold-standard techniques are required for determining the FC values of Sensibility and Specificity.
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Affiliation(s)
- Juliano Bordignon
- Departament of Microbiology, Immunology and Parasitology, Federal University of Santa Catarina, Florianópolis, SC, 88040-900, Brazil
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24
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Kao CL, Wu MC, Chiu YH, Lin JL, Wu YC, Yueh YY, Chen LK, Shaio MF, King CC. Flow cytometry compared with indirect immunofluorescence for rapid detection of dengue virus type 1 after amplification in tissue culture. J Clin Microbiol 2001; 39:3672-7. [PMID: 11574589 PMCID: PMC88405 DOI: 10.1128/jcm.39.10.3672-3677.2001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2000] [Accepted: 08/01/2001] [Indexed: 11/20/2022] Open
Abstract
Dengue virus (DV) was detected early in infected mosquito C6/36 cells by using indirect immunofluorescence (IF) in conjunction with flow cytometry. Three fixation-permeabilization methods and three DV serotype 1 (DEN-1)-specific monoclonal antibodies, 8-8 (anti-E), 16-4 (anti-NS1), and 15F3-1 (anti-NS1), were evaluated for the detection of DEN-1 in infected C6/36 cells. We found that these three monoclonal antibodies were capable of detecting DV in C6/36 cells as early as 24 h postinoculation by using a conventional indirect IF stain. Both 8-8 and 16-4 detected DV earlier and showed a greater number of DV-positive cells than 15F3-1. In flow cytometry, 3% paraformaldehyde plus 0.1% Triton X-100 with 16-4, the best fixation-permeabilization method for testing DV, showed higher sensitivity (up to 1 PFU) than indirect IF stain. The higher sensitivity of 16-4 in detecting DEN-1 was found with both IF and flow cytometry. Flow cytometry, which had a sensitivity similar to that of nested reverse transcription-PCR, was more sensitive in detecting DV in the infected mosquito cells 10 h earlier than the conventional IF stain. When clinical specimens were amplified in mosquito C6/36 cells and then assayed for DV using flow cytometry and conventional virus isolation at day 7 postinfection, both methods had 97.22% (35 out of 36) agreement. Moreover, among 12 positive samples which were detected by conventional culture method, the flow cytometry assay could detect DV in 58.33% (7 out of 12) of samples even at day 3 postinfection. In conclusion, both monoclonal antibodies 8-8 and 16-4 can be used for the early detection of DEN-1-infected C6/36 cells, with 16-4 (anti-NS1) being the best choice for the rapid diagnosis of DV by both the IF staining and flow cytometry methods.
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Affiliation(s)
- C L Kao
- School and Graduate Institute of Medical Technology, College of Medicine, National Taiwan University, Taipei, Republic of China.
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25
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Amjad M, Gillespie MA, Carlson RM, Karim MR. Flow cytometric evaluation of antiviral agents against human herpesvirus 6. Microbiol Immunol 2001; 45:233-40. [PMID: 11345533 DOI: 10.1111/j.1348-0421.2001.tb02612.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Antiviral activities of acyclovir (9-[(2-hydroxyethoxy) methyl] guanine, ACV), penciclovir (9-[4-hydroxy-3-(hydroxymethyl) butyl] guanine, PCV), ganciclovir ([9-(1,3-dihydroxy-2-propoxy) methyl] guanine, GCV), and foscarnet (phosphonoformic acid, PFA) were determined against Human Herpesvirus 6 (HHV-6) by flow cytometric technique. The technique is based on the detection of gp116 antigen expression in virus infected cells. Susceptibility was defined in terms of drug concentration which reduced the number of cells expressing HHV-6 gp116 antigen with a mean fluorescent intensity (MFI) by 50% as compared to virus infected untreated cells. GCV was found to be most effective against HHV-6 followed by PFA, PCV and ACV. For HHV-6A, the mean 50% inhibitory concentrations (IC50) of GCV and PFA were found to be 3.4 microM and 34.7 microM respectively, whereas the IC50 of ACV and PCV were found to be 53.7 microM and 37.9 microM respectively. For HHV-6B, the IC50 of GCV and PFA were found to be 5.7 microM and 71.4 microM respectively, whereas the IC50 of ACV and PCV were found to be 119.0 microM and 77.8 microM respectively. Flow cytometry is a valuable technique for the evaluation of antiviral compounds against viruses including HHV-6.
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Affiliation(s)
- M Amjad
- Department of Biology, University of Minnesota, Duluth, 55812, USA
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26
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Poirier-Toulemonde AS, Milpied N, Cantarovich D, Morcet JF, Billaudel S, Imbert-Marcille BM. Clinical relevance of direct quantification of pp65 antigenemia using flow cytometry in solid organ and stem cell transplant recipients. J Clin Microbiol 2000; 38:3143-9. [PMID: 10970347 PMCID: PMC87340 DOI: 10.1128/jcm.38.9.3143-3149.2000] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A total of 1,305 blood samples from 85 solid organ transplant (SOT) recipients and 25 stem cell transplant (SCT) recipients at risk for cytomegalovirus (CMV) infection were prospectively collected and tested using the shell vial assay (SVA) and a leukocytic qualitative PCR (q-PCR). Of these, 462 specimens were further tested by direct quantification of CMV antigenemia by flow cytometry (FC-Ag), 125 were tested with a quantitative competitive PCR, and 200 were tested for pp65 antigenemia using the slide method (S-Ag). Laboratory data were statistically analyzed according to the presence of CMV-related symptoms. In SOT and SCT recipients, active CMV infection occurred in 63.5 and 36%, respectively, and CMV disease occurred in 53 and 24%, respectively. FC-Ag results correlated better with q-PCR and S-Ag than with SVA. The first test found to be positive during follow-up was FC-Ag in 73% of cases. In SOT recipients, FC-Ag showed the highest sensitivity and negative predictive value for the diagnosis of any grade of CMV disease. For FC-Ag, the threshold beyond which CMV disease was highly probable seemed to lie at 0.20% positive polymorphonuclear leukocytes. FC-Ag appears to be a useful test for the early detection of CMV infection and the prediction of CMV disease.
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Affiliation(s)
- A S Poirier-Toulemonde
- Virology Laboratory EA-1156, Institute of Biology of Nantes University Hospital, Nantes University Hospital, 44093 Nantes Cedex 01, France
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27
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Abstract
Biological assays for adenoviral gene therapy vectors have included conventional procedures initially developed to detect wild-type adenoviruses. Standard virological assays to quantitate adenoviruses rely on the virus to infect and replicate in the host cell until a cytopathic effect is observed. The appearance of plaques, colonies of rounded, enlarged cells containing infectious virions, usually takes 2 to 3 weeks to reach an endpoint. We describe a flow cytometric bioassay for adenovirus which shortens the time from when the infection takes place to the time that biological titer is determined. A fluorescent focus-forming assay was one of the first rapid adenoviral bioassays developed. Virus titer was determined using fluorescence immunocytochemistry to detect adenovirus proteins and microscopy to count fluorescent foci in cultures of adenovirus-infected cells. In this study, we describe a flow cytometric assay performed on cells stained for adenovirus hexon capsid protein, where virus titer is determined based on the dose-dependent appearance of hexon-positive cells. Adenovirus hexon detection in infected cells can provide data to determine virus titer, inducible promoter function in vector-complementing cells, and vector replication in complementation-deficient cells.
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MESH Headings
- Adenovirus E1 Proteins/genetics
- Adenoviruses, Human/genetics
- Adenoviruses, Human/metabolism
- Adenoviruses, Human/physiology
- Antigens, Viral/analysis
- Antigens, Viral/biosynthesis
- Antigens, Viral/genetics
- Blotting, Southern
- Capsid/analysis
- Capsid/biosynthesis
- Capsid/genetics
- Capsid Proteins
- Cell Line
- DNA/analysis
- DNA, Viral/analysis
- Dexamethasone/pharmacology
- Flow Cytometry/methods
- Fluorescent Antibody Technique
- Gene Deletion
- Gene Expression Regulation, Viral/drug effects
- Gene Expression Regulation, Viral/genetics
- Genetic Complementation Test
- Genetic Therapy/methods
- Genetic Vectors/genetics
- Humans
- Microscopy, Fluorescence
- Promoter Regions, Genetic/genetics
- Sensitivity and Specificity
- Time Factors
- Tumor Cells, Cultured
- Viral Plaque Assay
- Virus Replication
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Affiliation(s)
- L S Weaver
- Genetic Therapy, Inc., 9 West Watkins Mill Road, Gaithersburg, Maryland 20878, USA
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28
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Abstract
Flow cytometry has been used to study virus-cell interactions for many years. This article critically reviews a number of reports on the use of flow cytometry for the detection of virus-infected cells directly in clinical samples and in virus-infected cultured cells. Examples are presented of the use of flow cytometry to screen antiviral drugs against human immunodeficiency virus (HIV), human cytomegalovirus, and herpes simplex viruses (HSV) and to perform drug susceptibility testing for these viruses. The use of reporter genes such as green fluorescent protein incorporated into HIV or HSV or into cells for the detection of the presence of virus, for drug susceptibility assay, and for viral pathogenesis is also covered. Finally, studies on the use of flow cytometry for studying the effect of virus infection on apoptosis and the cell cycle are summarized. It is hoped that this article will give the reader some understanding of the great potential of this technology for studying virus cell interactions.
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Affiliation(s)
- J J McSharry
- Department of Microbiology, Immunology and Molecular Genetics, Mail Code 68, 47 New Scotland Avenue, Albany, New York, 12208, USA
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29
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Abstract
The application of flow cytometry to microorganisms is as old as the technique itself, but it has historically been underexploited for microbial applications. This is now being reversed and microbiologists are ideally placed to benefit from recent technological advances. While earlier papers demonstrated the use of flow cytometry for studies of viability and taxonomy, recent developments in bioinformatics and reporter gene technologies are leading to novel applications in microbiology. Variants of green fluorescent protein have been used for the study of conditional microbial gene regulation in medically important host-pathogen interactions and fluorescence-activated cell sorting is being applied to the isolation of novel mutants in directed evolution studies. This paper reviews the reasons for the delay in the application of flow cytometry to microbial problems, the range of applications, and their limitations and considers the progress made in developing new strategies for use in microbiological investigations.
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Affiliation(s)
- M K Winson
- Institute of Biological Sciences, University of Wales, Aberystwyth, SY23 3DD, United Kingdom
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30
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Abstract
Classical microbiology techniques are relatively slow in comparison to other analytical techniques, in many cases due to the need to culture the microorganisms. Furthermore, classical approaches are difficult with unculturable microorganisms. More recently, the emergence of molecular biology techniques, particularly those on antibodies and nucleic acid probes combined with amplification techniques, has provided speediness and specificity to microbiological diagnosis. Flow cytometry (FCM) allows single- or multiple-microbe detection in clinical samples in an easy, reliable, and fast way. Microbes can be identified on the basis of their peculiar cytometric parameters or by means of certain fluorochromes that can be used either independently or bound to specific antibodies or oligonucleotides. FCM has permitted the development of quantitative procedures to assess antimicrobial susceptibility and drug cytotoxicity in a rapid, accurate, and highly reproducible way. Furthermore, this technique allows the monitoring of in vitro antimicrobial activity and of antimicrobial treatments ex vivo. The most outstanding contribution of FCM is the possibility of detecting the presence of heterogeneous populations with different responses to antimicrobial treatments. Despite these advantages, the application of FCM in clinical microbiology is not yet widespread, probably due to the lack of access to flow cytometers or the lack of knowledge about the potential of this technique. One of the goals of this review is to attempt to mitigate this latter circumstance. We are convinced that in the near future, the availability of commercial kits should increase the use of this technique in the clinical microbiology laboratory.
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31
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Essa S, Pacsa AS, Al-Attiyah R, El-Shazly A, Raghupathy R, Said T. The use of flow cytometry for the detection of CMV-specific antigen (pp65) in leukocytes of kidney recipients. Clin Transplant 2000; 14:147-51. [PMID: 10770420 DOI: 10.1034/j.1399-0012.2000.140208.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Flow cytometric assay (FCA) was used to detect a cytomegalovirus (CMV) specific antigen (pp65) in CMV-infected fibroblast cells and in leukocytes of kidney recipients. FCA distinguished clearly between the infected and non-infected fibroblast cells. Regarding transplant patients, the FCA was positive when the number of antigenemia assay (AA) positive cells was five or more per 5 x 10(4). Moreover, the percentage of antigenemia-positive cells by FCA correlated well with symptomatic CMV infections.
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Affiliation(s)
- S Essa
- Department of Microbiology, Faculty of Medicine, University of Kuwait.
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32
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Alvarez-Barrientos A, Arroyo J, Cantón R, Nombela C, Sánchez-Pérez M. Applications of flow cytometry to clinical microbiology. Clin Microbiol Rev 2000; 13:167-95. [PMID: 10755996 PMCID: PMC100149 DOI: 10.1128/cmr.13.2.167] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Classical microbiology techniques are relatively slow in comparison to other analytical techniques, in many cases due to the need to culture the microorganisms. Furthermore, classical approaches are difficult with unculturable microorganisms. More recently, the emergence of molecular biology techniques, particularly those on antibodies and nucleic acid probes combined with amplification techniques, has provided speediness and specificity to microbiological diagnosis. Flow cytometry (FCM) allows single- or multiple-microbe detection in clinical samples in an easy, reliable, and fast way. Microbes can be identified on the basis of their peculiar cytometric parameters or by means of certain fluorochromes that can be used either independently or bound to specific antibodies or oligonucleotides. FCM has permitted the development of quantitative procedures to assess antimicrobial susceptibility and drug cytotoxicity in a rapid, accurate, and highly reproducible way. Furthermore, this technique allows the monitoring of in vitro antimicrobial activity and of antimicrobial treatments ex vivo. The most outstanding contribution of FCM is the possibility of detecting the presence of heterogeneous populations with different responses to antimicrobial treatments. Despite these advantages, the application of FCM in clinical microbiology is not yet widespread, probably due to the lack of access to flow cytometers or the lack of knowledge about the potential of this technique. One of the goals of this review is to attempt to mitigate this latter circumstance. We are convinced that in the near future, the availability of commercial kits should increase the use of this technique in the clinical microbiology laboratory.
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Affiliation(s)
- A Alvarez-Barrientos
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Spain
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33
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Imbert-Marcille BM, Coste-Burel M, Robillard N, Foucaud-Gamen J, Billaudel S, Drouet E. Sequential use of paraformaldehyde and methanol as optimal conditions for the direct quantification of ZEBRA and rta antigens by flow cytometry. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2000; 7:206-11. [PMID: 10702494 PMCID: PMC95850 DOI: 10.1128/cdli.7.2.206-211.2000] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A technique was developed with flow cytometry to quantify the two immediate-early proteins ZEBRA and Rta, which are involved in the activation of Epstein-Barr virus replication. We evaluated four monoclonal antibodies on four cell lines (B95-8, RAJI, Namalwa, and P3HR1) with varying levels of expression of these replication-phase antigens. The Namalwa lymphoma cell line was used as a negative control. Four fixation-permeabilization procedures were compared. The preparation of cells with paraformaldehyde and methanol in sequence, and antigen detection with AZ125 and AR 5A9 monoclonal antibodies, were found to be the optimal conditions in these cell lines. Our procedure allowed ZEBRA antigen to be detected in 4.85% of peripheral blood mononuclear cells from a transplant recipient with a lymphoproliferative disease.
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34
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Abstract
Representatives from several different virus families (Baculoviridae, Herpesviridae, Myoviridae, Phycodnaviridae, Picornaviridae, Podoviridae, Retroviridae, and Siphoviridae) were stained using a variety of highly fluorescent nucleic acid specific dyes (SYBR Green I, SYBR Green II, OliGreen, PicoGreen) and examined using a standard flow cytometer equipped with a standard 15 mW argon-ion laser. The highest green fluorescence intensities were obtained using SYBR Green I. DNA viruses with genome sizes between 48.5 and 300 kb could easily be detected. The fluorescence signals of the small genome-sized RNA viruses (7.4-14.5 kb) were found at the limit of detection. No significant linear relationship could be found between genome size and the green fluorescence intensity of the SYBR Green I stained virus preparations. To our knowledge, this is the first report of detecting and discriminating between a wide range of different viruses directly using flow cytometry. This rapid and precise assay represents a new and promising tool in the field of virology.
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Affiliation(s)
- C P Brussaard
- Department of Microbiology, University of Bergen, Norway.
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35
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Díaz PV, Calhoun WJ, Hinton KL, Avendaño LF, Gaggero A, Simon V, Arredondo SM, Pinto R, Díaz A. Differential effects of respiratory syncytial virus and adenovirus on mononuclear cell cytokine responses. Am J Respir Crit Care Med 1999; 160:1157-64. [PMID: 10508802 DOI: 10.1164/ajrccm.160.4.9804075] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Respiratory syncytial virus (RSV) and adenovirus (Advs) serotype 3 (Adv3) and 7h (Adv7h) are associated with mild to severe respiratory infection and are indistinguishable during the acute phases of the illnesses. However, outcome and long-term prognosis are different with both infections. RSV infection is associated with later development of asthma, and Adv, mainly Adv7h, with severe lung damage, bronchiectasis, and hyperlucent lung. We hypothesized that this difference could be partly due to different immune responses induced by these viruses. To test this hypothesis we quantified TCD4+, TCD8+, and BCD19+ expressing the interleukin-2 receptor-alpha chain (CD25) and interferon-gamma (IFN-gamma), interleukin (IL)-10, and IL-4 in the supernatant of peripheral blood mononuclear cells (PBMC) from school children infected in vitro with and without RSV, Adv7h, and Adv3 and after phytohemagglutinin (PHA) stimulation in the presence or absence of these viruses at a multiplicity of infection (MOI) of 1. PBMC from every child produced more IL-10 (p </= 0.05) when infected with RSV than with Advs and noninfected control, and Adv induced more (p </= 0.05) IFN-gamma than did RSV and control. The IL-10/IFN-gamma ratio was significantly higher (p </= 0.05) in RSV-infected and significantly lower (p </= 0.05) in Adv-infected PBMC, than in noninfected cells. PHA-stimulated BCD19+ RSV- infected cells expressed more (p </= 0.05) IL-2R than did Adv-infected cells. These results suggest that Advs induce a Th-1-type immune response that is not seen with RSV. These patterns persist despite intersubject variation in the absolute quantity of cytokine produced.
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Affiliation(s)
- P V Díaz
- Programas de Patología y Virología, Instituto de Ciencias Biomédicas, Facultad de Medicina y Facultad de Ciencias, Universidad de Chile, Santiago, Chile
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36
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Abstract
This review describes the procedures for the use of fluorochrome labeled monoclonal antibodies and flow cytometry for the detection and quantification of virus infected cells. The application of this technology for (1) identifying virus infected cells in clinical specimens obtained from human cytomegalovirus (HCMV) and human immunodeficiency virus (HIV) infected individuals; (2) screening antiviral compounds active against HCMV, HDSV and HIV; and (3) performing drug susceptibility testing for HCMV, HSV and HIV clinical isolates are reviewed. The flow cytometry drug susceptibility assay is rapid, quantitative, and easily performed. It should be considered by anyone interested in performing drug susceptibility testing for any virus for which there are reliable monoclonal antibodies.
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37
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Detrick B, Hooks JJ, Keiser J, Tabbara I. Detection of cytomegalovirus proteins by flow cytometry in the blood of patients undergoing hematopoietic stem cell transplantation. Exp Hematol 1999; 27:569-75. [PMID: 10089921 DOI: 10.1016/s0301-472x(98)00076-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Cytomegalovirus (CMV) infection and associated diseases continue to be a major complication encountered by patients undergoing high-dose chemoradiotherapy and hematopoietic stem cell transplantation (HSCT). A number of studies revealed that identification of CMV in the blood of HSCT patients was a predictor of future CMV disease. The purpose of this study was to determine if CMV proteins detected by flow cytometry could be a rapid and more quantitative way to monitor CMV infections and CMV antigenemia in HSCT patients. Preliminary studies showed that CMV immediate early (IE), early (E), and late (L) tegument proteins were specifically identified in CMV-infected cell lines and not in uninfected cells. We evaluated CMV antigen detection by flow cytometry in blood samples collected before and after transplantation in 56 serially collected blood samples from 17 HSCT patients and CMV protein expression was compared to CMV isolation. CMV IE and E proteins were not detected in any of the samples analyzed. However, CMV L protein detection by flow cytometry correlated with virus isolation in serially collected blood samples. Samples from 14 patients were evaluated by both techniques, at the same time intervals. There was a 100% correlation (8/8) between the lack of CMV antigen detection by flow cytometry and the failure to isolate infectious virus. Moreover, 5 of 6 patients who were positive for CMV L antigen by flow cytometry also were positive by virus isolation techniques. When flow cytometry and virus isolation did not detect CMV antigen on the same day, CMV positivity was first detected by flow cytometry. Then, 1-2 weeks later, positive virus isolation was documented. This study indicates that flow cytometric identification of CMV antigenemia correlates with isolation of CMV in HSCT patients and may be a predictive test for the rapid detection of CMV in the blood.
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Affiliation(s)
- B Detrick
- Department of Pathology, George Washington University Medical Center, Washington, DC, USA
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38
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McSharry JJ, Lurain NS, Drusano GL, Landay AL, Notka M, O'Gorman MR, Weinberg A, Shapiro HM, Reichelderfer PS, Crumpacker CS. Rapid ganciclovir susceptibility assay using flow cytometry for human cytomegalovirus clinical isolates. Antimicrob Agents Chemother 1998; 42:2326-31. [PMID: 9736557 PMCID: PMC105827 DOI: 10.1128/aac.42.9.2326] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rapid, quantitative, and objective determination of the susceptibilities of human cytomegalovirus (HCMV) clinical isolates to ganciclovir has been assessed by an assay that uses a fluorochrome-labeled monoclonal antibody to an HCMV immediate-early antigen and flow cytometry. Analysis of the ganciclovir susceptibilities of 25 phenotypically characterized clinical isolates by flow cytometry demonstrated that the 50% inhibitory concentrations (IC50s) of ganciclovir for 19 of the isolates were between 1.14 and 6.66 microM, with a mean of 4.32 microM (+/-1.93) (sensitive; IC50 less than 7 microM), the IC50s for 2 isolates were 8.48 and 9.79 microM (partially resistant), and the IC50s for 4 isolates were greater than 96 microM (resistant). Comparative analysis of the drug susceptibilities of these clinical isolates by the plaque reduction assay gave IC50s of less than 6 microM, with a mean of 2.88 microM (+/-1.40) for the 19 drug-sensitive isolates, IC50s of 6 to 8 microM for the partially resistant isolates, and IC50s of greater than 12 microM for the four resistant clinical isolates. Comparison of the IC50s for the drug-susceptible and partially resistant clinical isolates obtained by the flow cytometry assay with the IC50s obtained by the plaque reduction assay showed an acceptable correlation (r2 = 0.473; P = 0.001), suggesting that the flow cytometry assay could substitute for the more labor-intensive, subjective, and time-consuming plaque reduction assay.
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Affiliation(s)
- J J McSharry
- Albany Medical College, Albany, New York 12208, USA.
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39
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Kuru L, Parkar MH, Griffiths GS, Newman HN, Olsen I. Flow cytometry analysis of gingival and periodontal ligament cells. J Dent Res 1998; 77:555-64. [PMID: 9539458 DOI: 10.1177/00220345980770040801] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Gingival and periodontal ligament (PDL) fibroblasts are the major cellular components of periodontal soft connective tissues, but the precise differences between these cells are not yet known. In the present study, we have therefore examined the phenotypic and functional features of the cells obtained from gingival and PDL biopsy samples. Spindle-shaped cells characteristic of fibroblasts were the main cell type observed in vitro, although epithelial cells were also present in primary gingival cell cultures. Flow cytometry was used to measure the size and granularity of the cultured cells, and showed that the gingival fibroblasts were smaller and less granular compared with the PDL cells. The expression of certain key extracellular matrix (ECM) proteins, fibronectin, collagen type I, and tenascin was measured by flow cytometry. Analysis of the fluorescence profiles of these cultures showed that the majority of cells expressed fibronectin and that the average fluorescence intensity of this antigen in the PDL cells was higher than that in the gingival fibroblasts. Moreover, the fibronectin-positive PDL cells apparently comprised two subpopulations which expressed fibronectin at different levels, suggesting that the cells in the PDL cultures were functionally heterogeneous. The level of collagen type I was also found to be up-regulated in the PDL compared with the gingival cells and, as with fibronectin, was expressed at two different levels by subsets of the PDL cells. In contrast, tenascin was expressed at very similar levels by both the gingival fibroblasts and PDL cells. In addition, measurement of alkaline phosphatase, a marker enzyme for mineralized tissue-forming cells, showed that the PDL cells had higher activity than the gingival fibroblasts and that the alkaline phosphatase activity in the PDL cells was far more markedly up-regulated by dexamethasone. Our findings demonstrate that, despite their similar spindle-shaped appearance, fibroblasts derived from gingival and PDL tissues appear to display distinct functional activities which are likely to play a vital part in the maintenance of tissue integrity and regenerative processes.
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Affiliation(s)
- L Kuru
- Department of Periodontology, Faculty of Dentistry, Marmara University, Istanbul, Turkey
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40
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Kesson AM, Zeng F, Cunningham AL, Rawlinson WD. The use of flow cytometry to detect antiviral resistance in human cytomegalovirus. J Virol Methods 1998; 71:177-86. [PMID: 9626951 DOI: 10.1016/s0166-0934(97)00214-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A method for detecting the antiviral susceptibility of human cytomegalovirus (HCMV) isolates to antiviral agents using flow cytometry was developed. This method has been used to detect the resistance phenotype of HCMV isolates to ganciclovir (GCV). The procedure involves infecting MRC-5 cells with 10(4) pfu HCMV for 120 h, then fixing and permeabilising the cells to allow intracellular labelling of the HCMV early and late antigens. The percentage reduction in the fluorescence positive population of HCMV-infected MRC-5 cells treated with GCV at concentrations of 20 or 50 microM compared with control cultures without GCV was determined. The IC50 defined as a < 50% reduction in the fluorescence positive population in cells infected in the presence of 20 microM GCV or an IC90 defined as a < 90% reduction in the fluorescence-positive population in cells infected in the presence of 50 microM GCV, correlated with resistance determined by a plaque reduction assay. The FACS assay is a rapid and reproducible method for detecting antiviral resistance of HCMV.
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Affiliation(s)
- A M Kesson
- Faculty of Medicine and Health Sciences, University of Newcastle, NSW, Australia.
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41
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McSharry JM, Lurain NS, Drusano GL, Landay A, Manischewitz J, Nokta M, O'Gorman M, Shapiro HM, Weinberg A, Reichelderfer P, Crumpacker C. Flow cytometric determination of ganciclovir susceptibilities of human cytomegalovirus clinical isolates. J Clin Microbiol 1998; 36:958-64. [PMID: 9542916 PMCID: PMC104668 DOI: 10.1128/jcm.36.4.958-964.1998] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A flow cytometric assay has been developed for the measurement of susceptibilities to ganciclovir of laboratory strains and clinical isolates of human cytomegalovirus (HCMV). The assay uses fluorochrome-labeled monoclonal antibodies to HCMV immediate-early and late antigens to identify HCMV-infected cells and flow cytometry to detect and quantitate the number of antigen-positive cells. By this assay, the 50 and 90% inhibitory concentrations (IC50 and IC90, respectively) of ganciclovir for the AD169 strain of HCMV were 1.7 and 9.2 microM, respectively, and the IC50 for the ganciclovir-resistant D6/3/1 derivative of the AD169 strain was greater than 12 microM. The ganciclovir susceptibilities of 17 HCMV clinical isolates were also determined by flow cytometric analysis of the effect of ganciclovir on late-antigen synthesis in HCMV-infected cells. The average IC50 of ganciclovir for drug-sensitive HCMV clinical isolates was 3.79 microM (+/-2.60). The plaque-reduction assay for these clinical isolates yielded an average IC50 of 2.80 microM (+/-1.46). Comparison of the results of the flow cytometry assays with those obtained from the plaque-reduction assays demonstrated acceptable bias and precision. Flow cytometric and plaque-reduction analysis of cells infected with ganciclovir-resistant clinical isolates failed to show a reduction in the percentage of late-antigen-positive cells or PFU, even at 96 microM ganciclovir. The flow cytometric assay for determining ganciclovir susceptibility of HCMV is quantitative, and objective, and potentially automatable, and its results are reproducible among laboratories.
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42
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Pavić I, Hartmann A, Zimmermann A, Michel D, Hampl W, Schleyer I, Mertens T. Flow cytometric analysis of herpes simplex virus type 1 susceptibility to acyclovir, ganciclovir, and foscarnet. Antimicrob Agents Chemother 1997; 41:2686-92. [PMID: 9420039 PMCID: PMC164189 DOI: 10.1128/aac.41.12.2686] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We established a quantitative flow cytometric method for determination of herpes simplex virus type 1 (HSV-1) susceptibility to acyclovir (ACV), ganciclovir, and foscarnet in vitro. Susceptibility was defined in terms of the drug concentration which reduced the number of cells expressing HSV-1 glycoprotein C (gpC) with a fluorescence intensity of > or =10(2) by 50% (IC50). Flow cytometry allowed us to use a high (1.0) as well as a low (0.005) multiplicity of infection, and determination of the IC50 was possible after one or more viral replicative cycles. IC50s were dependent on virus input and on time postinfection. In mixture experiments, 1 to 2% resistant viruses added to a sensitive strain could be detected. The results obtained by flow cytometry showed a good qualitative correlation with those achieved by cytopathic effect inhibitory assay. However, flow cytometry might detect more quantitative differences in drug susceptibility, especially among resistant strains, as confirmed also by determination of intracellular drug phosphorylation. The mean IC50s for ACV-sensitive strains were 0.45 to 1.47 microM, and those for ACV-resistant strains were between 140 and 3,134 microM. Flow cytometric analysis was fast and accurate, automatizable, and highly reproducible. Flow cytometry may be a more powerful tool than standard cytopathic effect-based assays and could have advantages for the detection of low levels of drug resistance or mixtures of sensitive and resistant virus strains.
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Affiliation(s)
- I Pavić
- Abteilung Virologie, Institut für Mikrobiologie, Universität Ulm, Germany
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43
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Imbert-Marcille BM, Robillard N, Poirier AS, Coste-Burel M, Cantarovich D, Milpied N, Billaudel S. Development of a method for direct quantification of cytomegalovirus antigenemia by flow cytometry. J Clin Microbiol 1997; 35:2665-9. [PMID: 9316930 PMCID: PMC230033 DOI: 10.1128/jcm.35.10.2665-2669.1997] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Cytomegalovirus (CMV) antigenemia was directly detected in polymorphonuclear leukocytes (PMNLs) from transplant recipients by using flow cytometry (FC). Two fixation and permeabilization methods and seven anti-CMV monoclonal antibodies (MAbs) were evaluated. 1C3, SL20, and NEA-9221 MAbs were more efficacious. The antigenemia detection threshold of FC was 0.05% positive PMNLs, and percentages correlated well with DNA viral load and the appearance of clinical symptoms.
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Affiliation(s)
- B M Imbert-Marcille
- Virology Laboratory, Institute of Biology of Nantes University Hospital, France.
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44
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Román M, Calhoun WJ, Hinton KL, Avendaño LF, Simon V, Escobar AM, Gaggero A, Díaz PV. Respiratory syncytial virus infection in infants is associated with predominant Th-2-like response. Am J Respir Crit Care Med 1997; 156:190-5. [PMID: 9230746 DOI: 10.1164/ajrccm.156.1.9611050] [Citation(s) in RCA: 201] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Viral infections have been associated with cellular immune responses and production of Th-1 cytokines. Respiratory syncytial virus (RSV), however, induces virus-specific IgE, which might be a consequence of a Th-2-like activation. To test this hypothesis we quantified interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) in the supernatant of peripheral blood mononuclear cells cultured for 24 and 48 h in the presence or absence of phytohemaglutinin and pokeweed mitogen and the lymphocyte phenotypes to analyze subsets and their activation markers, from 15 hospitalized infants during an acute lower respiratory infection caused by RSV and 17 healthy control infants from 1 to 15 mo of age. Compared with the control infants, those infected with RSV had an increase in the number of B-cells (p < 0.02) and decreases in both CD8+ T-cells (p < 0.01) and activated CD8+/CD25+ suppressor/ cytotoxic T-cells (p < 0.007). In RSV-infected infants, IFN-gamma production was subtotally suppressed, whereas IL-4 production was decreased to a lesser degree, giving significantly (p < 0.001) increased IL-4/IFN-gamma ratio compared with that in the control infants. These findings suggest a predominant Th-z-like response in RSV-infected infants, which could explain some aspects of the immunopathogenesis of RSV infection and the RSV-specific and nonspecific IgE antibody responses observed.
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Affiliation(s)
- M Román
- Departmentos Medicina Experimental Oriente y Microbiología, Facultad de Medicina, Universidad de Chile, Hospital Roberto del Río, Santiago, Chile
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