Vaccination of mice with 1918, 1943 and classical swine H1N1 virus-based inactive vaccines protects against Neth/09 lethal infection.

<p>Five weeks old C57B/6 were immunized with 15 µg of the indicated inactivated viruses or with 1918 VLP vaccine followed by a boost (15 µg) after two weeks. Four weeks after the first immunization, vaccinated mice were challenged with Neth/09 isolate at a dose of 50 LD₅₀ (7.9×10⁵ pfu). Mice were monitored for body weight loss and survival for 14 days as in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1000745#ppat-1000745-g001" target="_blank">Fig. 1</a>. (A) Body weight of classical swine H1N1 (Sw/30, NJ/76), 1918 VLP and human H1N1 Wei/43 vaccinated mice after challenge with Neth/09 (n = 4 or 5 mice/group) (D) Body weight of mice vaccinated with contemporary (from 1977–2007) H1N1 or H3N2 inactivated virus after challenge with Neth/09 (n = 4 or 5 mice/group). (B, E) Survival of mice vaccinated with H1N1 and H3N2 viruses post-challenge. (C, F) Viral titers in H1N1 and H3N2 vaccinated mice on days 3 and 6 p.c. Each data point represents the average viral titers from 2 or 3 mice. A single group of control (no vaccine) mice were used and are included in all the panels for direct comparison. The Cal/09 vaccinated group is also included on (A) and (B) for comparison.