FIGURE 9.

Immune protection of mice against lethal influenza A/Puerto Rico/8/34 (H1N1) challenge (n = 10). Mice were either inoculated intramuscularly with the PBS only, JOL1837 carrying empty vector (Sal-vector) and constructs JOL1917+1913 (im-Sal-HA-M2e) or intraperitoneally with constructs JOL1913+1917 (ip-Sal-HA-M2e) or orally with constructs JOL1913+1917 (po-Sal-HA-M2e). Mice were then challenged intranasally with 10⁶EID50 of lethal H1N1 virus at 4 weeks after primary immunization. Mice were monitored for weight loss (I) and survival (II) throughout a 14 day observation period. The results are presented in terms of percent of body weight and percent survival, respectively. (III) Lung tissues (n = 3) were harvested at 4 days post-challenge (dpc) and viral titers were determined by Reed and Muench method. The experiments were performed in triplicate and the results are presented as mean ± SD. ^∗p < 0.05; ^∗∗p < 0.01; dpc, days post-challenge; ^asignificant with respect to PBS, Sal-vector and po-Sal-HA-M2e groups; ^bsignificant with respect to Sal-vector and PBS controls; ns, non-significant.