Semi-perfusion cultures of suspension MDCK cells enable high cell concentrations and efficient influenza A virus production

Control and prevention of rapid influenza spread among humans depend on the availability of efficient and safe seasonal and pandemic vaccines, made primarily from inactivated influenza virus particles. Current influenza virus production processes rely heavily on embryonated chicken eggs or on cell culture as substrate for virus propagation. Today's efforts towards process intensification in animal cell culture could innovate viral vaccine manufacturing using high-yield suspension cells in high cell density perfusion processes. In this work, we present a MDCK cell line adapted to grow as single cell suspension with a doubling time of less than 20 h, achieving cell concentrations over 1 x 10(7) cells/mL in batch mode. Influenza A virus titer obtained in batch infections were 3.6 log(10)(HAU/100 mu L) for total- and 10(9) virions/mL for infectious virus particles (TCID50), respectively. In semi-perfusion mode concentrations up to 6 x 10(7) cells/mL, accumulated virus titer of 4.5 log(10)(HAU/100 mu L) aud infectious titer of almost 10(10 )virions/mL (TCID50) were possible. This exceeds results reported previously for cell culture-based influenza virus propagation by far and suggests perfusion cultures as the preferred method in viral vaccine manufacturing. (C) 2019 Published by Elsevier Ltd.