Figure 5.
HA-Specific Serum IgG2b Antibody Responses in Mice Immunized Once with BAd-H5HA or HAd-H5HA
Mice were immunized intramuscularly (IM) or intranasally (IN) once with 1 × 106 (A), 3 × 106 (B), 1 × 107 (C), 3 × 107 (D), or 1 × 108 (E) PFUs of BAd-H5HA or HAd-H5HA. For all dose groups, mice inoculated IM or IN with PBS or 1 × 108 PFUs of BAd-ΔE1E3 or HAd-ΔE1E3 served as negative or internal controls, respectively. Four weeks after inoculation, serum samples were collected, diluted to 1:50, and the development of HA-specific IgG2b antibody responses was monitored by ELISA. Data are represented as the mean ± SD of the optical density (OD) readings. Statistically significant responses are shown as compared with the PBS group (+), IN versus IM route of inoculation in the same group (*), or BAd-H5HA vector versus HAd-H5HA vector (ψ). * or +, significant at p < 0.05; ** or ++, significant at p < 0.01; +++ or ψψψ, significant at p < 0.001; and **** or ++++, significant at p < 0.0001. The statistical analysis was done by Bonferroni post-test and two-way ANOVA using GraphPad Prism 6. BAd-ΔE1E3, BAd empty vector; BAd-H5HA, bovine adenoviral vector expressing hemagglutinin (HA) of A/Hong Kong/156/97(H5N1) influenza virus; HAd-ΔE1E3, HAd empty vector; HAd-H5HA, human adenoviral vector expressing HA of A/Hong Kong/156/97(H5N1) influenza virus; ns, no significance at p > 0.05.