Intranasal immunization induces HA stalk-specific IgA antibodies.

<div><p>Mice from cohort III (cH9/1, cH6/1 and H1 soluble protein) that were vaccinated IN (dotted lines) with the addition of IVT SeV DI or poly(I:C) had detectable, HA stalk-specific IgA in the nasal washes. IM vaccinees (solid lines) did not have detectable stalk-specific IgA titers in nasal washes. Nasal washes of mice sublethally infected with influenza A/Puerto Rico/8/1934 were included as a positive control for reference. Error bars represent standard error of the mean for individual mice. </p> <p>* p<0.02. Significant differences in stalk-specific IgA titers in nasal washes were observed when comparing IN to IM immunization for both the IVT SeV DI and poly(I:C) groups.</p>