Fig 6.

In vivo clearance of H1N1 variants of influenza virus by the intranasal immunization of mice with A/Solomon Islands/3/2006 vaccines. Groups of mice (5 per group) were inoculated intranasally with PBS (PBS i.n.), a mixture of 1 μg A/Solomon Islands/3/2006 SV vaccine and 100 μg of γ-PGA-NPs (SV+NP i.n.), or 1 μg of A/Solomon Islands/3/2006 WV vaccine (WV i.n.), as described in Materials and Methods. Other groups of mice (5 per group) were immunized subcutaneously with PBS (PBS s.c.) or 1 μg of A/Solomon Islands/3/2006 WV vaccine (WV s.c.) as described in Materials and Methods. Fourteen days after the final immunization, the mice were infected with 10⁴ or 10⁵ PFU of A/Solomon Islands/3/2006, A/Brisbane/59/2007, A/New Caledonia/20/99, or A/PR/8/34. Two days after the infection, the BAL fluid was harvested and the PFU value for A/Solomon islands (A), A/Brisbane/59/2007 (B), A/New Caledonia/20/99 (C), or APR/8/34 (D) was assessed. Bars represent the means ± standard deviations from 5 mice. *, P < 0.05 versus the group of mice inoculated intranasally with PBS. #, P < 0.05 versus the group of mice inoculated subcutaneously with PBS.