The Effect of Calcium on Activity, Immunogenicity and Efficacy of a Recombinant N1/N2 Neuraminidase Vaccine

Despite the importance of immunity against neuraminidase (NA), NA content and immunogenicity is neglected in current influenza vaccines. To address this, a novel recombinant N1/N2 NA vaccine (NAV) was developed. Stability assays were used to determine optimal temperature and buffer conditions for vaccine storage. The effect of calcium-related enhancement of NA stability and activity on N1 and N2 immunogenicity and efficacy against viral challenge was assessed. Differences in activity between N1 and N2 and calcium-related activity enhancement did not translate into differences in immunogenicity or efficacy. NAV vaccinated mice showed robust antibody titers against N1 and N2, decreased viral titers, and decreased antiviral and inflammatory responses by transcriptomic analysis. The host lung transcriptional response to influeuza virus infection was assessed in mock vaccinated (PBS), NAV PBS and NAV DPBS-vaccinated mice at days 3 and 6 post-viral infection. All samples were compared to mock vaccinated, mock infected (PBS) animals.