Pilot-scale production of a highly efficacious and stable monoglycosylated influenza split virus vaccine

The yearly epidemics and unpredictable outbreaks of influenza have raisedserious concernsglobally and led to prioritizing the development of an effective vaccine toprotectagainst newly emerging variants. Previously, we demonstrated that monoglycosylated influenza virus vaccines derived from A/California/7/2009 or an updated A/Brisbane/02/2018 (IVR-190) vaccine strain recommended by WHO are superior to fully glycosylated vaccines and could broadly protect against past and new coming H1N1 variants. However, whether such a monoglycosylated virus vaccine can be mass-produced to meet clinical demands and stable enough to provide consistent efficacy against H1N1 viruses remains unclear. Herein, we developed a platform for the pilot-scale production of the monoglycosylated split virus vaccine from the IVR-190 strain (IVR-190_mg) with a robust and cost-effective manufacturing process. The critical parameters of inoculum dose, concentration of kifunensine, and optimized Endo H treatment process were comprehensively investigated. Several aims for preclinical studies of IVR-190_mg were achieved, including [i] the execution of three engineering batch runs to validate lot-to-lot consistency, [ii] the establishment of IVR-190_mg specifications to meet the acceptance criteria of a conventional influenza vaccine, [iii] an investigation of the stability profile of IVR-190_mg, and completion of a safety evaluation by conducting an animal toxicology study. The toxicology study under GLP guidance found no systemic toxicity after rabbits were vaccinated with IVR-190_mg. The serological data showed that IVR-190_mg is highly immunogenic and effective in inducing a cross-strain protective level of antibody immune responses, including hemagglutination-inhibition titers, viral neutralization activity, and broad HA- and NA-inhibiting antibody titers against past and new H1N1 viruses. In conclusion, this study provides efficacy and safety profiles of IVR-190_mg for further clinical study and shows that this vaccine without a glycan shield has great potential to be safe and protective against H1N1 variants.