Production of high titer attenuated poliovirus strains on the serum-free PER.C6 registered cell culture platform for the generation of safe and affordable next generation IPV

Background As poliovirus eradication draws closer, alternative Inactivated Poliovirus Vaccines (IPV) are needed to overcome the risks associated with continued use of the Oral Poliovirus Vaccine and of neurovirulent strains used during manufacture of conventional (c) IPV. We have previously demonstrated the susceptibility of the PER.C6 registered cell line to cIPV strains; here we investigated the suspension cell culture platform for growth of attenuated poliovirus strains. Methods We examined attenuated Sabin strain productivity on the PER.C6 registered cell platform compared to the conventional Vero cell platform. The suitability of the suspension cell platform for propagation of rationally-attenuated poliovirus strains (stabilized Sabin type 3 S19 derivatives and genetically attenuated and stabilized MonoCre(X) strains), was also assessed. Yields were quantified by infectious titer determination and D-antigen ELISA using either serotype-specific polyclonal rabbit sera for Sabin strains or monoclonal cIPV-strain-specific antibodies for cIPV, S19 and MonoCre(X) strains. Results PER.C6 registered cells supported the replication of Sabin strains to yields of infectious titers that were in the range of cIPV strains at 32.5 degree C. Sabin strains achieved 30-fold higher yields (p