Characterization of humoral immune responses induced by mucosal rAd/NP vaccination.

<p>BALB/c mice were immunized intranasally or sublingually with 1×10⁷ or 1×10⁸ PFU of rAd/NP. Two weeks after the primary immunization, animals that previously received rAd/NP via sublingual route were boosted with the same dose of rAd/NP used during the primary immunization. Control mice were immunized intranasally with 10⁸ PFU of rAd/Mock or with equal volume of PBS. (A) Systemic PR8-specific IgG antibody titers were measured by ELISA in sera harvested three weeks after their last immunization regimen and subsequent challenge with 10 LD₅₀ of PR8 virus at two different time points: pre-challenge and post-challenge. (B) Mucosal PR8-specific IgA titers were determined by ELISA in BAL from mice immunized i.n. or s.l. with rAd/NP and subsequent challenge with 10 LD₅₀ of PR8 virus at two different time points: pre-challenge and post-challenge. The results represent Log₂ endpoint values averaged from five individual mice.