FIG 4.

Nano SiO2 is effective in early life. (A) Seven-day-old CB6F1 mice were immunized i.m. with 0.1 μg H1N1 antigen alone or in combination with 50 μg dose of Nano SiO2. At 5 weeks later, mice were infected intranasally with H1N1 as adults. Serum anti-H1N1 IgG levels were assessed before infection. (B) Weight change after infection. (C to E) Levels of lung viral load (C), BAL fluid IgA (D), and CD8⁺ cells specific for influenza virus (E) were measured on day 7 after infection. Thin horizontal lines in panels A and C to E and points in panel B represent means of the results determined with n = ≥6 mice. *, P < 0.05; ***, P < 0.001 (measured by two-way ANOVA [B] or t tests [A and C]).