Protection of mice from lethal influenza virus challenge.

<p>A–B: Protection against A/California/04/2009 virus challenge. Mice intramuscularly immunized with a single dose of VLPs (10 µg) were challenged with a lethal dose (100 LD₅₀) of A/California/04/2009 virus at week 6 post immunization. Mice (n = 12) were monitored daily for 14 days for body weight changes (A) and survival rates (B). C–D: Protection against the antigenically distant A/PR8/1934 virus (10 LD₅₀). Body weight changes (C) and survival rates (D) are shown.