title: Live attenuated influenza viruses produced in a suspension process with avian AGE1.CR.pIX cells.
abstract: BACKGROUND
  Current influenza vaccines are trivalent or quadrivalent inactivated split or subunit vaccines administered intramuscularly, or live attenuated influenza vaccines (LAIV) adapted to replicate at temperatures below body temperature and administered intranasally. Both vaccines are considered safe and efficient, but due to differences in specific properties may complement each other to ensure reliable vaccine coverage. By now, licensed LAIV are produced in embryonated chicken eggs. In the near future influenza vaccines for human use will also be available from adherent MDCK or Vero cell cultures, but a scalable suspension process may facilitate production and supply with vaccines.
  
  
  RESULTS
  We evaluated the production of cold-adapted human influenza virus strains in the duck suspension cell line AGE1.CR.pIX using a chemically-defined medium. One cold-adapted A (H1N1) and one cold-adapted B virus strain was tested, as well as the reference strain A/PR/8/34 (H1N1). It is shown that a medium exchange is not required for infection and that maximum virus titers are obtained for 1 × 10⁻⁶ trypsin units per cell. 1 L bioreactor cultivations showed that 4 × 10⁶ cells/mL can be infected without a cell density effect achieving titers of 1 × 10⁸ virions/mL after 24 h.
  
  
  CONCLUSIONS
  Overall, this study demonstrates that AGE1.CR.pIX cells support replication of LAIV strains in a chemically-defined medium using a simple process without medium exchanges. Moreover, the process is fast with peak titers obtained 24 h post infection and easily scalable to industrial volumes as neither microcarriers nor medium replacements are required.
authors.affiliation: Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstr 1, 39106 Magdeburg, Germany. lohr@mpi-magdeburg.mpg.de
authors.forename: Verena
authors.initials: V
authors.lastname: Lohr
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Genzel
authors.forename: Ingo
authors.initials: I
authors.lastname: Jordan
authors.forename: Dietmar
authors.initials: D
authors.lastname: Katinger
authors.forename: Stefan
authors.initials: S
authors.lastname: Mahr
authors.forename: Volker
authors.initials: V
authors.lastname: Sandig
authors.forename: Udo
authors.initials: U
authors.lastname: Reichl
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D019149:Bioreactors; D018929:Cell Culture Techniques; D002460:Cell Line; D003470:Culture Media / Q000737:chemistry; D004372:Ducks; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000254:growth & development* / Q000276:immunology / Q000502:physiology; D007251:Influenza, Human / Q000517:prevention & control; D013696:Temperature; D014613:Vaccines, Attenuated / Q000096:biosynthesis / Q000276:immunology; D014776:Virus Cultivation; D014779:Virus Replication
chemical_list: D003470:Culture Media; D014613:Vaccines, Attenuated