FIG 4.

Rewiring HA and NA packaging signals enhances anti-N2 antibody response. (A) Mice were vaccinated twice with 10 μg either formalin-inactivated purified HK14 wt or HK14 swap virus. Mice were bled 4 weeks postboost, and sera were isolated for downstream analysis. IgG levels to recombinant tetrameric HK14 N2 protein (B) and trimeric HK14 H3 protein (C) were measured by ELISA. Log₁₀-transformed area under the curve (AUC) values were compared. (D) Levels of neuraminidase-inhibiting antibodies were measured by ELLA using a recombinant H1N2 virus expressing PR8 H1 and HK14 N2 (H1N2). Log₁₀-reciprocal 50% inhibitory concentration (IC₅₀) values were compared. P values listed for all comparisons were obtained by one-way ANOVA with Bonferroni correction. (E) Levels of antibody-dependent cellular cytotoxicity (ADCC)-active antibodies were assessed by ADCC reporter assay performed on MDCK cells infected with H1N2 virus. Sera from each group were pooled and run in duplicates.