Figure 5
Long-lasting protections against the heterosubtype influenza virus. Groups of mice immunized with 30 μg of 4sM2 protein twice at 2 week interval. Control mice were inoculated with 0.85% saline. Sera were collected on days 0, 21, and 180. An ELISA was performed in triplicate using the coated sM2 protein to confirm long lasting antibody level. Mice were challenged with lethal doses of A/Aquaticbird/Korea/W81/2005(H5N2) virus (10× MLD50) 6 months after the final immunization. (A) Absorbance of the IgG antibody specific to the sM2 protein. (B) Percent body weight loss and (C) percent survival, after infection with the influenza virus. Bars denote mean ± standard deviations. Comparisons of groups were analyzed by Student’s t-test and ANOVA; the differences were statistically significant (P < 0.05). Abbreviations: 4sM2, recombinant multimeric sM2 protein; NC, negative control.