Fig. 4.
DNA vaccination reduces viral load and protects against H1N1 influenza virus challenge. Immunized and control animals were challenged with either H1N1 A/California/2009 or A/Ohio/2007. Postchallenge viral loads were assessed for up to 7 days using a plaque reduction assay. Viral titers are presented as the log of the TCID50 for each animal, with bars indicating means and error bars indicating SEMs. Differences between immunized animals and controls were analyzed for statistical significance using a Mann-Whitney t test. P values of less than 0.05 are indicated: * represents a P value between 0.05 and 0.001, while ** indicates a value of ≤0.001. θ indicates a value that is nonsignificant when Bonferroni's adjustment is applied.