title: Influenza virus intracellular replication dynamics, release kinetics, and particle morphology during propagation in MDCK cells.
abstract: Influenza viruses are respiratory pathogens and can cause severe disease. The best protection against influenza is provided by annual vaccination. These vaccines are produced in embryonated chicken eggs or using continuous animal cell lines. The latter processes are more flexible and scalable to meet the growing global demand. However, virus production in cell cultures is more expensive. Hence, further research is needed to make these processes more cost-effective and robust. We studied influenza virus replication dynamics to identify factors that limit the virus yield in adherent Madin-Darby canine kidney (MDCK) cells. The cell cycle stage of MDCK cells had no impact during early infection. Yet, our results showed that the influenza virus RNA synthesis levels out already 4 h post infection at a time when viral genome segments are exported from the nucleus. Nevertheless, virus release occurred at a constant rate in the following 16 h. Thereafter, the production of infectious viruses dramatically decreased, but cells continued to produce particles contributing to the hemagglutination (HA) titer. The majority of these particles from the late phase of infection were deformed or broken virus particles as well as large membranous structures decorated with viral surface proteins. These changes in particle characteristics and morphology need to be considered for the optimization of influenza virus production and vaccine purification steps. Moreover, our data suggest that in order to achieve higher cell-specific yields, a prolonged phase of viral RNA synthesis and/or a more efficient release of influenza virus particles is required.
authors.affiliation: Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106, Magdeburg, Germany. frensing@mpi-magdeburg.mpg.de.|Chair of Bioprocess Engineering, Otto-von-Guericke University Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany. frensing@mpi-magdeburg.mpg.de.
authors.forename: Timo
authors.initials: T
authors.lastname: Frensing
authors.affiliation: Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106, Magdeburg, Germany.
authors.forename: Sascha Y
authors.initials: SY
authors.lastname: Kupke
authors.affiliation: Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106, Magdeburg, Germany.
authors.forename: Mandy
authors.initials: M
authors.lastname: Bachmann
authors.affiliation: Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106, Magdeburg, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Fritzsche
authors.affiliation: Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106, Magdeburg, Germany.
authors.forename: Lili E
authors.initials: LE
authors.lastname: Gallo-Ramirez
authors.affiliation: Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106, Magdeburg, Germany.|Chair of Bioprocess Engineering, Otto-von-Guericke University Magdeburg, Universitätsplatz 2, 39106, Magdeburg, Germany.
authors.forename: Udo
authors.initials: U
authors.lastname: Reichl
mesh_terms: D000818:Animals; D002460:Cell Line; D004285:Dogs; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000254:growth & development*; D007252:Influenza Vaccines / Q000096:biosynthesis* / Q000276:immunology; D007251:Influenza, Human / Q000276:immunology / Q000517:prevention & control*; D061985:Madin Darby Canine Kidney Cells; D012367:RNA, Viral / Q000096:biosynthesis*; D014776:Virus Cultivation / Q000379:methods*; D014779:Virus Replication
chemical_list: D007252:Influenza Vaccines; D012367:RNA, Viral
keywords: Influenza virus; Vaccine production; Virus particle morphology; Virus release