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Malik T, Klenow L, Karyolaimos A, Gier JWD, Daniels R. Silencing Transcription from an Influenza Reverse Genetics Plasmid in E. coli Enhances Gene Stability. ACS Synth Biol 2023; 12:432-445. [PMID: 36716395 PMCID: PMC9942234 DOI: 10.1021/acssynbio.2c00358] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Reverse genetics (RG) systems have been instrumental for determining the molecular aspects of viral replication, pathogenesis, and for the development of therapeutics. Here, we demonstrate that genes encoding the influenza surface antigens hemagglutinin and neuraminidase have varying stability when cloned into a common RG plasmid and transformed into Escherichia coli. Using GFP as a reporter, we demonstrate that E. coli expresses the target genes in the RG plasmid at low levels. Incorporating lac operators or a transcriptional terminator into the plasmid reduced expression and stabilized the viral genes to varying degrees. Sandwiching the viral gene between two lac operators provided the largest contribution to stability and we confirmed the stabilization is Lac repressor-dependent and crucial for subsequent plasmid propagations in E. coli. Viruses rescued from the lac operator-stabilized plasmid displayed similar kinetics and titers to the original plasmid in two different viral backbones. Together, these results indicate that silencing transcription from the plasmid in E. coli helps to maintain the correct influenza gene sequence and that the lac operator addition does not impair virus production. It is envisaged that sandwiching DNA segments between lac operators can be used for reducing DNA segment instability in any plasmid that is propagated in E. coli which express the Lac repressor.
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Affiliation(s)
- Tahir Malik
- Division
of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Laura Klenow
- Division
of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland 20993, United States
| | - Alexandros Karyolaimos
- Department
of Biochemistry and Biophysics, Stockholm
University, 10691 Stockholm, Sweden
| | - Jan-Willem de Gier
- Department
of Biochemistry and Biophysics, Stockholm
University, 10691 Stockholm, Sweden
| | - Robert Daniels
- Division
of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland 20993, United States,
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2
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Neumann G. Influenza Reverse Genetics-Historical Perspective. Cold Spring Harb Perspect Med 2021; 11:cshperspect.a038547. [PMID: 31964649 DOI: 10.1101/cshperspect.a038547] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The generation of wild-type, mutant, and reassortant influenza viruses from viral cDNAs (reverse genetics) is now a basic molecular virology technique in many influenza virus laboratories. Here, I describe the original RNA polymerase I reverse genetics system and the modifications that have been developed in past years. Together, these technologies have made possible many advances in basic and applied influenza virology that would not have been otherwise attainable, including the revival and study of extinct influenza viruses, the rapid characterization of emerging influenza viruses, the generation of conventional influenza vaccines, and the development of novel influenza vaccines.
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Affiliation(s)
- Gabriele Neumann
- Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53711, USA
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3
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Abstract
Influenza virus epidemics are caused when seasonal influenza viruses (i.e., those circulating in humans) acquire mutations in the antigenic sites of the viral hemagglutinin (HA) protein that prevent the antibodies present in people from binding to the virus and blocking virus interaction with cellular receptors. To date, vaccination is the best protective option against seasonal influenza viruses. Because influenza viruses frequently acquire mutations in their antigenic sites, vaccine viruses need to be updated regularly. Here, we present an experimental system that allows the simulation of influenza virus evolution in the test tube. By using this system, we can identify antigenic variants that may emerge among natural influenza viruses in the near future. This information would help in the selection and prioritization of variants for vaccine production.
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Affiliation(s)
- Gabriele Neumann
- Department of Pathobiological Sciences, Influenza Research Institute, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Shufang Fan
- Department of Pathobiological Sciences, Influenza Research Institute, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Yoshihiro Kawaoka
- Department of Pathobiological Sciences, Influenza Research Institute, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA.
- Division of Virology, Department of Microbiology and Immunology, University of Tokyo, Tokyo, Japan.
- International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
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4
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Finch C, Li W, Perez DR. Design of alternative live attenuated influenza virus vaccines. Curr Top Microbiol Immunol 2015; 386:205-35. [PMID: 25005928 DOI: 10.1007/82_2014_404] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Each year due to the ever-evolving nature of influenza, new influenza vaccines must be produced to provide protection against the influenza viruses in circulation. Currently, there are two mainstream strategies to generate seasonal influenza vaccines: inactivated and live-attenuated. Inactivated vaccines are non-replicating forms of whole influenza virus, while live-attenuated vaccines are viruses modified to be replication impaired. Although it is widely believed that by inducing both mucosal and humoral immune responses the live-attenuated vaccine provides better protection than that of the inactivated vaccine, there are large populations of individuals who cannot safely receive the LAIV vaccine. Thus, safer LAIV vaccines are needed to provide adequate protection to these populations. Improvement is also needed in the area of vaccine production. Current strategies relying on traditional tissue culture-based and egg-based methods are slow and delay production time. This chapter describes experimental vaccine generation and production strategies that address the deficiencies in current methods for potential human and agricultural use.
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Affiliation(s)
- Courtney Finch
- Department of Veterinary Medicine, College Park and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD, USA
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5
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Genzel Y, Reichl U. Continuous cell lines as a production system for influenza vaccines. Expert Rev Vaccines 2014; 8:1681-92. [DOI: 10.1586/erv.09.128] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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6
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A cell-based screening system for influenza A viral RNA transcription/replication inhibitors. Sci Rep 2013; 3:1106. [PMID: 23346363 PMCID: PMC3551287 DOI: 10.1038/srep01106] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 01/02/2013] [Indexed: 12/14/2022] Open
Abstract
Although two classes of antivirals, NA inhibitors and M2 ion channel blockers, are licensed for influenza treatment, dual resistant mutants, including highly pathogenic H5N1 viruses, have appeared. Alternative treatment options are, therefore, needed. Influenza A viral RNA (vRNA) transcription/replication is a promising target for antiviral development, since it is essential for virus replication. Accordingly, an efficient and reliable method to identify vRNA transcription/replication inhibitors is desirable. Here, we developed a cell-based screening system by establishing a cell line that stably expresses influenza viral ribonucleoprotein complex (vRNP). Compound library screening using this cell line allowed us to identify a compound that inhibits vRNA transcription/replication by using reporter protein expression from virus-like RNA as a readout and virus replication in vitro. vRNP-expressing cells have potential as a simple and convenient high-throughput screening (HTS) system, and, thus, are promising to identify vRNA transcription/replication inhibitors for various RNA viruses, especially for primary screens.
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7
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Engelhardt OG. Many ways to make an influenza virus--review of influenza virus reverse genetics methods. Influenza Other Respir Viruses 2012; 7:249-56. [PMID: 22712782 PMCID: PMC5779834 DOI: 10.1111/j.1750-2659.2012.00392.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Methods to introduce targeted mutations into a genome or, in the context of virology, into a virus are subsumed under the term reverse genetics (RG). Influenza viruses are important human pathogens that continue to surprise us. The development of RG for influenza viruses has greatly expanded our knowledge about influenza virus and enabled researchers to generate influenza viruses with rationally designed genotypes. Currently, a wide array of influenza virus RG methods is available. These can all be traced to fundamental principles essential in any RG system for negative-strand RNA viruses. This review gives an overview of these principles and of the multitude of RG methods, categorising them by technical characteristics.
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Affiliation(s)
- Othmar G Engelhardt
- Division of Virology, National Institute for Biological Standards and Control, Health Protection Agency, Potters Bar, UK.
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Abstract
The ability to modify influenza viruses at will has revolutionized influenza research. Reverse genetics has been used to generate mutant or reassortant influenza viruses to assess their replication, virulence, pathogenicity, host range, and transmissibility. Moreover, this technology is now being used to generate approved influenza virus vaccines and develop novel vaccines to combat seasonal and (future) pandemic influenza viruses. Several variations of the original system have been established, all of which are considerably robust and efficient.
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Affiliation(s)
- Gabriele Neumann
- Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
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9
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Enhanced growth of influenza vaccine seed viruses in vero cells mediated by broadening the optimal pH range for virus membrane fusion. J Virol 2011; 86:1405-10. [PMID: 22090129 DOI: 10.1128/jvi.06009-11] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Vaccination is one of the most effective preventive measures to combat influenza. Prospectively, cell culture-based influenza vaccines play an important role for robust vaccine production in both normal settings and urgent situations, such as during the 2009 pandemic. African green monkey Vero cells are recommended by the World Health Organization as a safe substrate for influenza vaccine production for human use. However, the growth of influenza vaccine seed viruses is occasionally suboptimal in Vero cells, which places limitations on their usefulness for enhanced vaccine production. Here, we present a strategy for the development of vaccine seed viruses with enhanced growth in Vero cells by changing an amino acid residue in the stem region of the HA2 subunit of the hemagglutinin (HA) molecule. This mutation optimized the pH for HA-mediated membrane fusion in Vero cells and enhanced virus growth 100 to 1,000 times in the cell line, providing a promising strategy for cell culture-based influenza vaccines.
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Yoshida T, Kondoh M, Ojima M, Mizuguchi H, Yamagishi Y, Sakamoto N, Yagi K. Adenovirus vector-mediated assay system for hepatitis C virus replication. Nucleic Acids Res 2011; 39:e64. [PMID: 21306994 PMCID: PMC3105406 DOI: 10.1093/nar/gkr047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The efficient delivery of the hepatitis C virus (HCV) RNA subgenomic replicon into cells is useful for basic and pharmaceutical studies. The adenovirus (Ad) vector is a convenient and efficient tool for the transduction of foreign genes into cells in vitro and in vivo. However, an Ad vector expressing the HCV replicon has never been developed. In the present study, we developed Ad vector containing an RNA polymerase (pol) I-dependent expression cassette and a tetracycline-controllable RNA pol I-dependent expression system. We prepared a hybrid promoter from the tetracycline-responsive element and the RNA pol I promoter. Ad vector particles coding the hybrid promoter-driven HCV replicon could be amplified, and interferon, an inhibitor of HCV replication, reduced HCV replication in cells transduced with the Ad vector coding HCV replicon. This is the first report of the development of an Ad vector-mediated HCV replicon system.
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Affiliation(s)
- Takeshi Yoshida
- Laboratory of Bio-Functional Molecular Chemistry, Department of Biochemistry and Molecular Biology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
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11
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Steitz J, Barlow PG, Hossain J, Kim E, Okada K, Kenniston T, Rea S, Donis RO, Gambotto A. A candidate H1N1 pandemic influenza vaccine elicits protective immunity in mice. PLoS One 2010; 5:e10492. [PMID: 20463955 PMCID: PMC2864737 DOI: 10.1371/journal.pone.0010492] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 04/08/2010] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND In 2009 a new pandemic disease appeared and spread globally. The recent emergence of the pandemic influenza virus H1N1 first isolated in Mexico and USA raised concerns about vaccine availability. We here report our development of an adenovirus-based influenza H1N1 vaccine tested for immunogenicity and efficacy to confer protection in animal model. METHODS We generated two adenovirus(Ad5)-based influenza vaccine candidates encoding the wildtype or a codon-optimized hemagglutinin antigen (HA) from the recently emerged swine influenza isolate A/California/04/2009 (H1N1)pdm. After verification of antigen expression, immunogenicity of the vaccine candidates were tested in a mouse model using dose escalations for subcutaneous immunization. Sera of immunized animals were tested in microneutalization and hemagglutination inhibition assays for the presence of HA-specific antibodies. HA-specific T-cells were measured in IFNgamma Elispot assays. The efficiency of the influenza vaccine candidates were evaluated in a challenge model by measuring viral titer in lung and nasal turbinate 3 days after inoculation of a homologous H1N1 virus. CONCLUSIONS/SIGNIFICANCE A single immunization resulted in robust cellular and humoral immune response. Remarkably, the intensity of the immune response was substantially enhanced with codon-optimized antigen, indicating the benefit of manipulating the genetic code of HA antigens in the context of recombinant influenza vaccine design. These results highlight the value of advanced technologies in vaccine development and deployment in response to infections with pandemic potential. Our study emphasizes the potential of an adenoviral-based influenza vaccine platform with the benefits of speed of manufacture and efficacy of a single dose immunization.
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Affiliation(s)
- Julia Steitz
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Peter G. Barlow
- Molecular Virology and Vaccines Branch, Influenza Division, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Jaber Hossain
- Molecular Virology and Vaccines Branch, Influenza Division, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Eun Kim
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Kaori Okada
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Tom Kenniston
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Sheri Rea
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Ruben O. Donis
- Molecular Virology and Vaccines Branch, Influenza Division, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Andrea Gambotto
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
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12
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Robertson JS, Engelhardt OG. Developing vaccines to combat pandemic influenza. Viruses 2010; 2:532-546. [PMID: 21994647 PMCID: PMC3185603 DOI: 10.3390/v2020532] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 01/28/2010] [Accepted: 01/29/2010] [Indexed: 11/16/2022] Open
Abstract
Influenza vaccine manufacturers require antigenically relevant vaccine viruses that have good manufacturing properties and are safe to use. In developing pandemic vaccine viruses, reverse genetics has been employed as a rational approach that can also be used effectively to attenuate the highly virulent H5N1 virus and at the same time place the H5 HA and N1 NA on a background of PR8, a virus that has been used over many decades to provide high yielding vaccine viruses. Reverse genetics has also been used successfully alongside classical reassorting techniques in the development of (swine flu) pandemic A(H1N1)v vaccine viruses.
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Affiliation(s)
- James S. Robertson
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +44-1707-641304; Fax: +44-1707-641050
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13
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Feng L, Li F, Zheng X, Pan W, Zhou K, Liu Y, He H, Chen L. The mouse Pol I terminator is more efficient than the hepatitis delta virus ribozyme in generating influenza-virus-like RNAs with precise 3' ends in a plasmid-only-based virus rescue system. Arch Virol 2009; 154:1151-6. [PMID: 19526191 DOI: 10.1007/s00705-009-0422-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Accepted: 06/01/2009] [Indexed: 11/25/2022]
Abstract
Reverse genetics systems for generating recombinant influenza viruses are based on two different mechanisms for obtaining the 3' end of the viral RNA: one uses the self-cleaving hepatitis delta virus ribozyme (HDVR), and the other uses the murine RNA polymerase I (Pol I) terminator. In this study, we employed EGFP and Renilla luciferase reporter constructs to compare the efficiency of both methods. Our results indicate that the murine Pol I terminator was more efficient than the HDVR, which will be helpful in choosing an influenza virus rescue system, as well as in establishing other RNA virus rescue systems.
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Affiliation(s)
- Liqiang Feng
- Center for Vaccines and Biotherapeutics, Guangzhou Institute of Biomedicine and Health, China
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14
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Koudstaal W, Hartgroves L, Havenga M, Legastelois I, Ophorst C, Sieuwerts M, Zuijdgeest D, Vogels R, Custers J, de Boer-Luijtze E, de Leeuw O, Cornelissen L, Goudsmit J, Barclay W. Suitability of PER.C6® cells to generate epidemic and pandemic influenza vaccine strains by reverse genetics. Vaccine 2009; 27:2588-93. [DOI: 10.1016/j.vaccine.2009.02.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Revised: 02/02/2009] [Accepted: 02/11/2009] [Indexed: 11/16/2022]
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15
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Establishment of canine RNA polymerase I-driven reverse genetics for influenza A virus: its application for H5N1 vaccine production. J Virol 2007; 82:1605-9. [PMID: 18045936 DOI: 10.1128/jvi.01876-07] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
In the event of a new influenza pandemic, vaccines whose antigenicities match those of circulating strains must be rapidly produced. Here, we established an alternative reverse genetics system for influenza virus using the canine polymerase I (PolI) promoter sequence that works efficiently in the Madin-Darby canine kidney cell line, a cell line approved for human vaccine production. Using this system, we were able to generate H5N1 vaccine seed viruses more efficiently than can be achieved with the current system that uses the human PolI promoter in African green monkey Vero cells, thus improving pandemic vaccine production.
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