Nasal and sublingual vaccination results in protection against Influenza challenge infection.

<p>Serum-antigen-specific IgG antibody responses (n = 6 per group) were recorded one week after 3 DNA primes and a single HA boost (<b>a</b>, <b>b</b> and <b>c</b>). Specifically, a 20 µg/30 µl volume of plasmid DNA was administered three times, every two weeks, before a single 10 µg/30 µl HA protein boost. Serum anti-HA antibody concentrations are expressed as group means (ng/ml+SEM). One week after the final vaccination, mice were infected with 5HA units of Influenza X-31 in 100 µl (<b>d</b>). Body weights for DNA prime protein boost vaccinations (−) and single protein vaccination (−) groups are expressed as a mean percentage of total weight relative to day 0. Mean IFN-γ T cell responses were assessed on day 4 post infection using a commercial ELISPOT assay coated with HA protein (<b>e</b>). Results represent the means of (n = 6) IFN-γ SFU/million splenocytes on day 4 post-infection. Statistical significance was assessed using Mann Whitney U test with **<i>p</i><0.005 and *<i>p</i><0.05. Data are representative of two independent experiments.