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Guan L, Ping J, Lopes TJS, Fan S, Presler R, Neumann G, Kawaoka Y. Development of an Enhanced High-Yield Influenza Vaccine Backbone in Embryonated Chicken Eggs. Vaccines (Basel) 2023; 11:1364. [PMID: 37631932 PMCID: PMC10459923 DOI: 10.3390/vaccines11081364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/08/2023] [Accepted: 08/09/2023] [Indexed: 08/28/2023] Open
Abstract
Vaccination is an efficient approach to preventing influenza virus infections. Recently, we developed influenza A and B virus vaccine backbones that increased the yield of several vaccine viruses in Madin-Darby canine kidney (MDCK) and African green monkey kidney (Vero) cells. These vaccine backbones also increased viral replication in embryonated chicken eggs, which are the most frequently used platform for influenza vaccine manufacturing. In this study, to further increase the viral titers in embryonated chicken eggs, we introduced random mutations into the 'internal genes' (i.e., all influenza viral genes except those encoding the hemagglutinin and neuraminidase proteins) of the influenza A virus high-yield virus backbone we developed previously. The randomly mutated viruses were sequentially passaged in embryonated chicken eggs to select variants with increased replicative ability. We identified a candidate that conferred higher influenza virus growth than the high-yield parental virus backbone. Although the observed increases in virus growth may be considered small, they are highly relevant for vaccine manufacturers.
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Affiliation(s)
- Lizheng Guan
- Department of Pathobiological Sciences, School of Veterinary Medicine, Influenza Research Institute, University of Wisconsin-Madison, Madison, WI 53711, USA (T.J.S.L.); (R.P.)
| | - Jihui Ping
- Department of Pathobiological Sciences, School of Veterinary Medicine, Influenza Research Institute, University of Wisconsin-Madison, Madison, WI 53711, USA (T.J.S.L.); (R.P.)
| | - Tiago J. S. Lopes
- Department of Pathobiological Sciences, School of Veterinary Medicine, Influenza Research Institute, University of Wisconsin-Madison, Madison, WI 53711, USA (T.J.S.L.); (R.P.)
| | - Shufang Fan
- Department of Pathobiological Sciences, School of Veterinary Medicine, Influenza Research Institute, University of Wisconsin-Madison, Madison, WI 53711, USA (T.J.S.L.); (R.P.)
| | - Robert Presler
- Department of Pathobiological Sciences, School of Veterinary Medicine, Influenza Research Institute, University of Wisconsin-Madison, Madison, WI 53711, USA (T.J.S.L.); (R.P.)
| | - Gabriele Neumann
- Department of Pathobiological Sciences, School of Veterinary Medicine, Influenza Research Institute, University of Wisconsin-Madison, Madison, WI 53711, USA (T.J.S.L.); (R.P.)
| | - Yoshihiro Kawaoka
- Department of Pathobiological Sciences, School of Veterinary Medicine, Influenza Research Institute, University of Wisconsin-Madison, Madison, WI 53711, USA (T.J.S.L.); (R.P.)
- Division of Virology, Department of Microbiology and Immunology, International Research Center for Infectious Diseases, The Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
- The Research Center for Global Viral Diseases, National Center for Global Health and Medicine Research Institute, Tokyo 162-8655, Japan
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Hussain S, Turnbull ML, Pinto RM, McCauley JW, Engelhardt OG, Digard P. Segment 2 from influenza A(H1N1) 2009 pandemic viruses confers temperature-sensitive haemagglutinin yield on candidate vaccine virus growth in eggs that can be epistatically complemented by PB2 701D. J Gen Virol 2019; 100:1079-1092. [PMID: 31169484 DOI: 10.1099/jgv.0.001279] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Candidate vaccine viruses (CVVs) for seasonal influenza A virus are made by reassortment of the antigenic virus with an egg-adapted strain, typically A/Puerto Rico/8/34 (PR8). Many 2009 A(H1N1) pandemic (pdm09) high-growth reassortants (HGRs) selected this way contain pdm09 segment 2 in addition to the antigenic genes. To investigate this, we made CVV mimics by reverse genetics (RG) that were either 6 : 2 or 5 : 3 reassortants between PR8 and two pdm09 strains, A/California/7/2009 (Cal7) and A/England/195/2009, differing in the source of segment 2. The 5 : 3 viruses replicated better in MDCK-SIAT1 cells than the 6 : 2 viruses, but the 6 : 2 CVVs gave higher haemagglutinin (HA) antigen yields from eggs. This unexpected phenomenon reflected temperature sensitivity conferred by pdm09 segment 2, as the egg HA yields of the 5 : 3 viruses improved substantially when viruses were grown at 35 °C compared with 37.5 °C, whereas the 6 : 2 virus yields did not. However, the authentic 5 : 3 pdm09 HGRs, X-179A and X-181, were not markedly temperature sensitive despite their PB1 sequences being identical to that of Cal7, suggesting compensatory mutations elsewhere in the genome. Sequence comparisons of the PR8-derived backbone genes identified polymorphisms in PB2, NP, NS1 and NS2. Of these, PB2 N701D affected the temperature dependence of viral transcription and, furthermore, improved and drastically reduced the temperature sensitivity of the HA yield from the 5 : 3 CVV mimic. We conclude that the HA yield of pdm09 CVVs can be affected by an epistatic interaction between PR8 PB2 and pdm09 PB1, but that this can be minimized by ensuring that the backbones used for vaccine manufacture in eggs contain PB2 701D.
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Affiliation(s)
- Saira Hussain
- 1 The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, EH25 9RG, UK.,2 The Francis Crick Institute, London, NW1 1AT, UK
| | - Matthew L Turnbull
- 1 The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, EH25 9RG, UK
| | - Rute M Pinto
- 1 The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, EH25 9RG, UK
| | | | - Othmar G Engelhardt
- 3 National Institute for Biological Standards and Control, South Mimms, Potters Bar, Hertfordshire, EN6 3QG, UK
| | - Paul Digard
- 1 The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, EH25 9RG, UK
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3
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Mutation of Influenza A Virus PA-X Decreases Pathogenicity in Chicken Embryos and Can Increase the Yield of Reassortant Candidate Vaccine Viruses. J Virol 2019; 93:JVI.01551-18. [PMID: 30381488 PMCID: PMC6321911 DOI: 10.1128/jvi.01551-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 10/25/2018] [Indexed: 01/08/2023] Open
Abstract
Influenza A virus is a widespread pathogen that affects both humans and a variety of animal species, causing regular epidemics and sporadic pandemics, with major public health and economic consequences. A better understanding of virus biology is therefore important. The primary control measure is vaccination, which for humans mostly relies on antigens produced in eggs from PR8-based viruses bearing the glycoprotein genes of interest. However, not all reassortants replicate well enough to supply sufficient virus antigen for demand. The significance of our research lies in identifying that mutation of the PA-X gene in the PR8 strain of virus can improve antigen yield, potentially by decreasing the pathogenicity of the virus in embryonated eggs. The PA-X protein of influenza A virus has roles in host cell shutoff and viral pathogenesis. While most strains are predicted to encode PA-X, strain-dependent variations in activity have been noted. We found that PA-X protein from the A/PR/8/34 (PR8) strain had significantly lower repressive activity against cellular gene expression than PA-X proteins from the avian strains A/turkey/England/50-92/91 (H5N1) (T/E) and A/chicken/Rostock/34 (H7N1). Loss of normal PA-X expression, either by mutation of the frameshift site or by truncating the X open reading frame (ORF), had little effect on the infectious virus titer of PR8 or PR8 7:1 reassortants with T/E segment 3 grown in embryonated hens’ eggs. However, in both virus backgrounds, mutation of PA-X led to decreased embryo mortality and lower overall pathology, effects that were more pronounced in the PR8 strain than in the T/E reassortant, despite the low shutoff activity of the PR8 PA-X. Purified PA-X mutant virus particles displayed an increased ratio of hemagglutinin (HA) to nucleoprotein (NP) and M1 compared to values for their wild-type (WT) counterparts, suggesting altered virion composition. When the PA-X gene was mutated in the background of poorly growing PR8 6:2 vaccine reassortant analogues containing the HA and neuraminidase (NA) segments from H1N1 2009 pandemic viruses or from an avian H7N3 strain, HA yield increased up to 2-fold. This suggests that the PR8 PA-X protein may harbor a function unrelated to host cell shutoff and that disruption of the PA-X gene has the potential to improve the HA yield of vaccine viruses. IMPORTANCE Influenza A virus is a widespread pathogen that affects both humans and a variety of animal species, causing regular epidemics and sporadic pandemics, with major public health and economic consequences. A better understanding of virus biology is therefore important. The primary control measure is vaccination, which for humans mostly relies on antigens produced in eggs from PR8-based viruses bearing the glycoprotein genes of interest. However, not all reassortants replicate well enough to supply sufficient virus antigen for demand. The significance of our research lies in identifying that mutation of the PA-X gene in the PR8 strain of virus can improve antigen yield, potentially by decreasing the pathogenicity of the virus in embryonated eggs.
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Wu NC, Xie J, Zheng T, Nycholat CM, Grande G, Paulson JC, Lerner RA, Wilson IA. Diversity of Functionally Permissive Sequences in the Receptor-Binding Site of Influenza Hemagglutinin. Cell Host Microbe 2018; 21:742-753.e8. [PMID: 28618270 DOI: 10.1016/j.chom.2017.05.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/24/2017] [Accepted: 05/27/2017] [Indexed: 12/21/2022]
Abstract
Influenza A virus hemagglutinin (HA) initiates viral entry by engaging host receptor sialylated glycans via its receptor-binding site (RBS). The amino acid sequence of the RBS naturally varies across avian and human influenza virus subtypes and is also evolvable. However, functional sequence diversity in the RBS has not been fully explored. Here, we performed a large-scale mutational analysis of the RBS of A/WSN/33 (H1N1) and A/Hong Kong/1/1968 (H3N2) HAs. Many replication-competent mutants not yet observed in nature were identified, including some that could escape from an RBS-targeted broadly neutralizing antibody. This functional sequence diversity is made possible by pervasive epistasis in the RBS 220-loop and can be buffered by avidity in viral receptor binding. Overall, our study reveals that the HA RBS can accommodate a much greater range of sequence diversity than previously thought, which has significant implications for the complex evolutionary interrelationships between receptor specificity and immune escape.
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Affiliation(s)
- Nicholas C Wu
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jia Xie
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Tianqing Zheng
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Corwin M Nycholat
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Geramie Grande
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - James C Paulson
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA; Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Richard A Lerner
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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5
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Suzuki Y, Odagiri T, Tashiro M, Nobusawa E. Development of an Influenza A Master Virus for Generating High-Growth Reassortants for A/Anhui/1/2013(H7N9) Vaccine Production in Qualified MDCK Cells. PLoS One 2016; 11:e0160040. [PMID: 27454606 PMCID: PMC4959774 DOI: 10.1371/journal.pone.0160040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 07/12/2016] [Indexed: 11/20/2022] Open
Abstract
In 2013, the first case of human infection with an avian influenza A virus (H7N9) was reported in China, and the human infection with this virus has continued as of 2016. At the request of the WHO, we have successfully developed candidate reassortant vaccine virus using A/Anhui/1/2013 and the high egg-growth master virus A/PR/8/1934. Recent plans regarding influenza vaccine production include using cell-cultured systems in Japan and several other countries. However, egg-based vaccine viruses are not always suitable for cell-cultured vaccine production due to potential issues with growth, protein yield and antigenic stability. Therefore, in this study, we have developed a high-growth master virus (hg-PR8) adapted to qualified NIID-MDCK cells that are competent for vaccine production. The virus hg-PR8 was obtained after 20 serial passages of A/Puerto Rico/8/1934 (PR8) in NIID-MDCK cells. The viral titer of hg-PR8 was 108.6 plaque-forming units per milliliter (PFU/mL). Seven amino acid substitutions were identified in the amino acid sequences of PB2, PB1, PA, NA, M and NS of hg-PR8 compared to the sequence of the original PR8 (org-PR8) strain. The growth capacities of the reassortant viruses, which possess heterologous internal genes from hg-PR8 or org-PR8, indicated that the amino acid changes in PB2 and NS2 similarly affected growth capacity in NIID-MDCK cells. To assess the suitability of hg-PR8 as a master virus, we generated 6:2 reassortant viruses possessing the HA and NA segments from A/Anhui/1/2013 (H7N9) and the remaining segments from hg-PR8. The virus titers of the reassortant strains were 107−108 PFU/mL. The antigenicity of the viruses was stable during ten passages of the viruses in NIID-MDCK cells. In comparison with the egg-based reassortant vaccine viruses with identical HA and NA segments, the hg-PR8-based viruses showed 1.5- to 2-fold higher protein yields in NIID-MDCK cells.
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MESH Headings
- Adaptation, Biological
- Amino Acid Substitution
- Animals
- Antigens, Viral/genetics
- Antigens, Viral/immunology
- Antigens, Viral/metabolism
- Cell Line
- Cells, Cultured
- Dogs
- Genes, Viral
- Glycosylation
- Humans
- Influenza A Virus, H7N9 Subtype/genetics
- Influenza A Virus, H7N9 Subtype/immunology
- Influenza A Virus, H7N9 Subtype/metabolism
- Influenza Vaccines/immunology
- Influenza, Human/immunology
- Influenza, Human/prevention & control
- Mutation
- Reassortant Viruses/genetics
- Reassortant Viruses/immunology
- Reassortant Viruses/metabolism
- Virus Replication/genetics
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Affiliation(s)
- Yasushi Suzuki
- Influenza Virus Research Center, National Institute of Infectious Diseases, Musashi-murayama, Tokyo, Japan
| | - Takato Odagiri
- Influenza Virus Research Center, National Institute of Infectious Diseases, Musashi-murayama, Tokyo, Japan
| | - Masato Tashiro
- Influenza Virus Research Center, National Institute of Infectious Diseases, Musashi-murayama, Tokyo, Japan
| | - Eri Nobusawa
- Influenza Virus Research Center, National Institute of Infectious Diseases, Musashi-murayama, Tokyo, Japan
- * E-mail:
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6
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Development of high-yield influenza A virus vaccine viruses. Nat Commun 2015; 6:8148. [PMID: 26334134 PMCID: PMC4569720 DOI: 10.1038/ncomms9148] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 07/23/2015] [Indexed: 01/13/2023] Open
Abstract
Vaccination is one of the most cost-effective ways to prevent infection. Influenza vaccines propagated in cultured cells are approved for use in humans, but their yields are often suboptimal. Here, we screened A/Puerto Rico/8/34 (PR8) virus mutant libraries to develop vaccine backbones (defined here as the six viral RNA segments not encoding haemagglutinin and neuraminidase) that support high yield in cell culture. We also tested mutations in the coding and regulatory regions of the virus, and chimeric haemagglutinin and neuraminidase genes. A combination of high-yield mutations from these screens led to a PR8 backbone that improved the titres of H1N1, H3N2, H5N1 and H7N9 vaccine viruses in African green monkey kidney and Madin–Darby canine kidney cells. This PR8 backbone also improves titres in embryonated chicken eggs, a common propagation system for influenza viruses. This PR8 vaccine backbone thus represents an advance in seasonal and pandemic influenza vaccine development. The availability of high-yield virus strains remains an important bottleneck in the rapid production of influenza vaccines. Here, the authors report the development of influenza A vaccine backbone that improves the virus yield of various seasonal and pandemic influenza vaccine strains in cell culture.
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7
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Ye J, Wen F, Xu Y, Zhao N, Long L, Sun H, Yang J, Cooley J, Todd Pharr G, Webby R, Wan XF. Error-prone pcr-based mutagenesis strategy for rapidly generating high-yield influenza vaccine candidates. Virology 2015; 482:234-43. [PMID: 25899178 DOI: 10.1016/j.virol.2015.03.051] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 12/25/2014] [Accepted: 03/27/2015] [Indexed: 01/07/2023]
Abstract
Vaccination is the primary strategy for the prevention and control of influenza outbreaks. However, the manufacture of influenza vaccine requires a high-yield seed strain, and the conventional methods for generating such strains are time consuming. In this study, we developed a novel method to rapidly generate high-yield candidate vaccine strains by integrating error-prone PCR, site-directed mutagenesis strategies, and reverse genetics. We used this method to generate seed strains for the influenza A(H1N1)pdm09 virus and produced six high-yield candidate strains. We used a mouse model to assess the efficacy of two of the six candidate strains as a vaccine seed virus: both strains provided complete protection in mice against lethal challenge, thus validating our method. Results confirmed that the efficacy of these candidate vaccine seed strains was not affected by the yield-optimization procedure.
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Affiliation(s)
- Jianqiang Ye
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA
| | - Feng Wen
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA
| | - Yifei Xu
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA
| | - Nan Zhao
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA
| | - Liping Long
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA
| | - Hailiang Sun
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA
| | - Jialiang Yang
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA
| | - Jim Cooley
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, MS, USA
| | - G Todd Pharr
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA
| | - Richard Webby
- Department of Infectious Diseases, St. Jude Children׳s Research Hospital, Memphis, TN, USA
| | - Xiu-Feng Wan
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS, USA.
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8
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Dormitzer PR. Rapid Production of Synthetic Influenza Vaccines. Curr Top Microbiol Immunol 2014; 386:237-73. [DOI: 10.1007/82_2014_399] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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