Table 3.
Growth properties in mice of mutant VD5 viruses possessing human-like amino acids
Mice (three per group) were infected intranasally with 100 p.f.u. virus. Organs were collected from infected mice on days 1 and 3 post-infection (p.i.) for virus titration. Individual titres were recorded when virus was not recovered from all three animals. –, Virus was not recovered (detection limit for lung and nasal turbinates was <1.6 log10 p.f.u. g−1 and for brain was <1.1 log10 p.f.u. g−1).
| Virus | Day p.i. | Virus titre (mean±sd log10 p.f.u. g−1) in: | ||
|---|---|---|---|---|
| Lung | Nasal turbinates | Brain | ||
| VD5 | 1 | – | – | – |
| 3 | – | – | – | |
| VD5K | 1 | 4.7±0.9 | – | – |
| 3 | 7.0±0.4 | 3.0±0.7 | – | |
| VD5K-PB2-9N | 1 | 4.9±0.5 | – | – |
| 3 | 7.0±0.2 | 2.9, 6.0 | – | |
| VD5K-PB2-199S | 1 | 4.8±0.3 | – | – |
| 3 | 7.1±0.3 | 2.2 | – | |
| VD5K-PB2-368K | 1 | 3.9±0.3 | – | – |
| 3 | 6.9±0.6 | 3.9 | – | |
| VD5K-PA-142E | 1 | 7.0±0.3* | 2.3 | – |
| 3 | 7.5±0.1 | 3.7, 4.4 | 1.4 | |
| VD5K-PA-142N | 1 | 5.7±0.5 | – | – |
| 3 | 7.2±0.4 | 5.7, 5.2 | – | |
| VD5K-PA-421I | 1 | 4.7±0.4 | – | – |
| 3 | 6.8±0.1 | – | – | |
| VD5K-NP-33I | 1 | 4.0±0.3 | – | – |
| 3 | 6.3±0.1 | 4.8 | – | |
| VD5K-NP-357K | 1 | 4.6±0.1 | – | – |
| 3 | 6.2±0.2 | 2.2 | – | |
*The virus titre in lungs of mice infected with VD5K-PA-142E was significantly higher than that of VD5K-infected mice on day 1 p.i., as determined by Student's t-test (P<0.02).