Table 3.
Protection of mice against lethal heterologous influenza A virus challenge by DNA prime-intranasal protein boost strategy based on NP vaccine
| Group |
Immunization |
Lung virus titer (log10TCID50/ml)a |
Survival rate (No. Of survivors/no. tested) | |||
|---|---|---|---|---|---|---|
| 3 days | 5 days | 7 days | ||||
| DNA prime | rNP boost | |||||
| D1P1 |
once |
once |
6.41±0.13b |
4.61±0.35b |
0.67±0.58b |
10/10b |
| D2P1 |
twice |
once |
6.22±0.16b |
4.00±0.33b |
0.41±0.71b |
10/10b |
| Control | - | - | 7.17±0.24 | 6.72±0.25 | 6.17±0.58 | 0/10 |
Mice of three groups were immunized as described above. 3 weeks after the last immunization, mice were challenged with a lethal dose (5×LD50) of influenza virus A/Chicken/JiangSu/07/2002 (H9N2). Bronchoalveolar washes from three mice in each group were collected 3 days, 5 days and 7 days post-infection for titration of lung virus respectively.
The survival rate of mice 21 days post-infection was determined.
a Results are expressed as mean ± SD of tested mice in each group.
b Displays significant difference compared with mouse in control groups (P<0.05).