FIG 2.

Dose titration of NanoSiO2. (A) Adult female CB6F1 mice were immunized i.m. with 0.1 μg H1N1 HA antigen alone or in combination with a 1-, 10-, or 50-μg dose of NanoSiO2. At 4 weeks later, mice were infected i.n. with influenza virus. Serum anti-H1N1 IgG levels were assessed before infection. (B) Weight change during H1N1 infection. (C) Influenza virus M gene RNA levels in lung on day 7 after infection. (D) BAL fluid anti-H1N1 IgA levels on day 7 after infection. (E) Levels of CD8⁺ cells specific for H1 influenza virus determined by fluorescence-activated cell sorter (FACS) analysis. (F to H) Correlation of day 7 serum anti-H1N1 IgG (F) and BAL fluid anti-H1N1 IgA (G) levels and influenza virus-specific proportion of CD8⁺ cells (H) to day 7 infection weight loss percentages. Points in panel A and thin horizontal lines in panels A and C to E represent means of the results determined with n = ≥4 mice. *, P < 0.05; **, P < 0.01 (measured by one-way or two-way analysis of variance [ANOVA]). Data in panels G, H, and I represent results of correlation by Pearson r test.