• Optimized a range of culture conditions for a chimeric recombinant influenza virus rA/B-H3 in MDCK suspension cells. • The optimized vaccine demonstrated complete resistance to the lethal attack of wild-type H3N2 influenza virus. • Demonstrated the reliability of the MDCK suspension cell platform for the production of the chimeric H3N2 candidate vaccine. Influenza viruses cause annual seasonal epidemics and occasional pandemics. Vaccination is most effective at preventing influenza virus infections. Suspensions of the Madin–Darby canine kidney (MDCKs) cell line are used to manufacture cell-based influenza vaccines. In this study, we tested and optimized a range of culture conditions for a chimeric recombinant influenza virus rA/B-H3 in MDCK suspension cells, revealing that the optimal inoculation conditions were multiplicity of infection of 0.001, cell concentration of infection of 4.0 × 10 6 cells/mL, addition of 2 μg/mL of L-1-tosylamide-2-phenylethyl chloromethyl ketone, time of harvest of 72 h. The optimal parameter setting in a 5-L bioreactor was 50% dissolved oxygen and pH 7.2 ± 0.05. The rA/B-H3 has stability genetic after 15 passages in MDCKs. The rA/B-H3 had several immune responsesin mice. Hemagglutination inhibition (HAI) antibodies, micro-neutralizing (MN) antibodies, and IgG antibodies were induced in immunized mice, and the mucosal IgA antibody responses were detected in their lung lavage fluids. The IFN-γ-secretion and IL-4-secretion by the mouse splenocytes were induced after stimulation with the specific H3N2 HA protein. Immunized mice resisted the lethal challenge with a wild-type H3N2 influenza virus. This study demonstrated the reliability of the MDCK suspension cell platform for the production of the chimeric H3N2 candidate vaccine, and the rA/B-H3 candidate vaccine is a potentially safe efficial vaccine.
Wu et al. (Wed,) studied this question.