Table 4. Protection of mice against lethal heterosubtypic H3N2 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 | 5.20 ± 0.19b | 9/10ab | A/Guizhou/54/1989 (H3N2) |
| B | NP | 100 | 5.40 ± 0.37b | 4/10b | A/Guizhou/54/1989 (H3N2) |
| C | PBS | − | 6.40 ± 0.21 | 0/10 | A/Guizhou/54/1989 (H3N2) |
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/Guizhou/54/1989 (H3N2) 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).