Mice immunized with rBac-HA virus show protection against challenge with heterosubtypic H5N1 virus.

<p>BALB/c mice (n = 5/group) were immunized twice on day 0 and 16 with 3×10⁶ PFU or 3×10⁷ PFU of rBac-HA virus via intranasal route. Each group of mice was challenged by intranasal administration with 50 LD₅₀ of H5N1 influenza virus. (A) Weight loss was monitored daily for 14 days after challenge. The results were expressed in percent body weight compared to beginning of the trial. (B) Survival of all group of mice were also monitored for 14 days. *, Statistical significance with “Bac-ctrl” group (p<0.05). <i>Bac-ctrl</i>, Bac-control.