Table 1.
Survival of mice immunized with NS1 attenuated influenza A viruses and challenged with wild-type influenza A/PR8 virus
| Group | Survivors
|
||||
|---|---|---|---|---|---|
| Immunization
|
After immunization | After challenge*
|
|||
| Virus | Dose, pfu | 1 × 105pfu | 5 × 106pfu | ||
| A | A/delNS1 | 1.0 × 106 | 9/9 | 5/5 | 4/4 |
| B | 3.3 × 104 | 5/5 | 0/5 | ND | |
| C | A/NS1-99 | 1.0 × 106 | 8/10 | 5/5 | 3/3 |
| D | 3.3 × 104 | 9/10 | 3/5 | 4/4 | |
| E | A/PR8 | 2.0 × 103 | 1/5 | ND | 1/1 |
| F | PBS | 0 | 6/6 | 0/6 | ND |
*
Mice were challenged with 1 × 105 pfu (100 LD50) or with 5 × 106 pfu (5,000 LD50) influenza A/PR8 virus 4 wk after immunization. ND, not determined.