FIG 3.

Induction of PspA-specific IgG and IgA levels in nasal wash fluids (A) and BALF (B) and IgG levels in sera (C), as well as IgG1 and IgG2a levels in sera (D). Mice were intranasally inoculated with medium, HA-KO/GFP virus, or HA-KO/PspA virus with a 2-week interval between the inoculations. Samples from six mice from each group were collected 2 weeks after the final vaccination. PspA-specific antibodies were detected by use of an ELISA. The value of IgG in panel D is identical to that of the IgG of HA-KO/PspA in panel C. Results are expressed as the means of the reciprocal titer log₂ (± SD). Statistically significant differences between groups were determined by using the Dunnett method. The asterisk indicates a significant difference from samples taken from mice inoculated with medium (*, P < 0.05).