title: A Vero-cell-adapted vaccine donor strain of influenza A virus generated by serial passages.
abstract: A cell culture-based vaccine production system is preferred for the large-scale production of influenza vaccines and has advantages for generating vaccines against highly pathogenic influenza A viruses. Vero cells have been widely used in human vaccine manufacturing, and the safety of these cells has been well demonstrated. However, the most commonly used influenza-vaccine donor virus, A/Puerto Rico/8/1934 (PR8) virus, does not grow efficiently in Vero cells. Therefore, we adapted the PR8 virus to Vero cells by continuous passaging, and a high-growth strain was obtained after 20 passages. Sequence analysis and virological assays of the adapted strain revealed that mutations in four viral internal genes (NP, PB1, PA and NS1) were sufficient for adaptation. The recombinant virus harboring these mutations (PR8-4mut) displayed accelerated viral transport into the nucleus and increased RNP activity. Importantly, the PR8-4mut could serve as a backbone donor virus to support the growth of the H7N1, H9N2 and H5N1 avian viruses and the H1N1 and H3N2 human viruses in Vero cells without changing its pathogenicity in either chicken embryos or mice. Thus, our work describes the generation of a Vero-adapted, high-yield PR8-4mut virus that may serve as a promising candidate for an influenza-vaccine donor virus.
authors.affiliation: Key Laboratory of Molecular Virology & Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Weibin
authors.initials: W
authors.lastname: Hu
authors.affiliation: Key Laboratory of Molecular Virology & Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Molecular Virology & Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Qinglin
authors.initials: Q
authors.lastname: Han
authors.affiliation: Key Laboratory of Molecular Virology & Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: National Institute of Diagnostics and Vaccine Development in Infectious Disease, State Key Laboratory of Cellular Stress Biology, School of Life Science, Xiamen University, Xiamen 361005, China.
authors.forename: Yixin
authors.initials: Y
authors.lastname: Chen
authors.affiliation: National Institute of Diagnostics and Vaccine Development in Infectious Disease, State Key Laboratory of Cellular Stress Biology, School of Life Science, Xiamen University, Xiamen 361005, China.
authors.forename: Ningshao
authors.initials: N
authors.lastname: Xia
authors.affiliation: Shanghai Institute of Biological Products, Shanghai 200052, China.
authors.forename: Ze
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Chinese Center for Disease Control and Prevention, Beijing 100052, China.
authors.forename: Yuelong
authors.initials: Y
authors.lastname: Shu
authors.affiliation: Key Laboratory of Molecular Virology & Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China. Electronic address: kxu@sibs.ac.cn.
authors.forename: Ke
authors.initials: K
authors.lastname: Xu
authors.affiliation: Key Laboratory of Molecular Virology & Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China. Electronic address: bsun@sibs.ac.cn.
authors.forename: Bing
authors.initials: B
authors.lastname: Sun
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D002642:Chick Embryo; D002645:Chickens / Q000821:virology; D002522:Chlorocebus aethiops; D005814:Genes, Viral; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000254:growth & development; D053122:Influenza A Virus, H3N2 Subtype / Q000235:genetics / Q000254:growth & development; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics / Q000254:growth & development; D057916:Influenza A Virus, H7N1 Subtype / Q000235:genetics / Q000254:growth & development; D053127:Influenza A Virus, H9N2 Subtype / Q000235:genetics / Q000254:growth & development; D009980:Influenza A virus / Q000235:genetics / Q000254:growth & development* / Q000276:immunology* / Q000302:isolation & purification; D007252:Influenza Vaccines / Q000032:analysis; D051379:Mice; D009154:Mutation; D016865:Reassortant Viruses / Q000235:genetics* / Q000254:growth & development; D012261:Ribonucleoproteins / Q000378:metabolism; D017421:Sequence Analysis; D012692:Serial Passage; D014709:Vero Cells / Q000821:virology*; D014764:Viral Proteins / Q000378:metabolism; D014776:Virus Cultivation
chemical_list: D007252:Influenza Vaccines; D012261:Ribonucleoproteins; D014764:Viral Proteins
keywords: Influenza A virus vaccine; Serial passages; Vero-cell adaptation