FIG 2.

Disruption of nasal bacteria induces the HA-specific antibody responses after intranasal vaccination. (A and B) Mice were immunized intranasally with quadrivalent HA vaccine with or without poly(I:C) or lysozyme twice in a 3-week interval. Two weeks later, the nasal washes and sera were collected and the HA-specific nasal IgA and serum IgG titers were determined by ELISA. Open circles indicate values for individual mice. The data are from three independent experiments (mean ± SEM). **, P < 0.01; ***, P < 0.001 (one-way ANOVA and Tukey’s test).