Fig 5.

In vivo clearance of homotype and subtype of influenza virus strains by intranasal immunization of mice with A/PR/8/34 vaccines. Groups of mice (5 per group) were inoculated intranasally with PBS, a mixture of 1 μg of A/PR/8/34 SV vaccine and 100 μg of γ-PGA-NPs (SV+NP), or 1 μg of A/PR/8/34 WV vaccine (WV) as described in Materials and Methods. Fourteen days after the final immunization, the mice were infected with 10⁴ or 10⁵ PFU of A/PR/8/34 (H1N1), A/Hiroshima/53/2005 (H3N2), or B/Malaysia/2506/2004. Two days after the infection, the BAL fluid was harvested and the number of PFU of A/PR/8/34 (A), A/Hiroshima/52/2005 (B), or B/Malaysia/2506/2004 (C) was assessed. Bars represent the means ± standard deviations from 5 mice. *, P < 0.05 versus the group of mice inoculated intranasally with PBS.