Table 3. Protection of mice against lethal heterosubtypic H9N2 challenge by intranasal administration of TAT-NP or NP.
| Group | Immunogen | Dose (μg) | Lung virus titers (Log10TCID50/mL) | Survival (survivors/total) | Challenge virus |
|---|---|---|---|---|---|
| A | TAT-NP | 100 | 4.28 ± 0.54b | 9/10ab | A/Chicken/Jiangsu/7/2002 (H9N2) |
| B | NP | 100 | 4.89 ± 0.18b | 3/10b | A/Chicken/Jiangsu/7/2002 (H9N2) |
| C | PBS | − | 5.56 ± 0.20 | 0/10 | A/Chicken/Jiangsu/7/2002 (H9N2) |
Note: BABL/c mice were randomly divided into three groups. Mice were immunized intranasally with NP or TAT-NP vaccine, whereas control animals received PBS. Two weeks after the last immunization, mice were challenged with a lethal dose (10 × LD50) of influenza A/Chicken/Jiangsu/7/2002 (H9N2) virus. BALF from three mice in each group were collected 3 days post-infection for virus titration in the lungs respectively. The survival rate of mice (n = 10) was determined at 14 days post-infection. The t-test was used to determine difference in viral load. The survival rates were evaluated by log-rank (Mantel–Cox) test.
aDisplays statistically significant difference compared with the same dose NP group (P < 0.05).
bDisplays statistically significant difference compared with the PBS group (P < 0.05).