Table 2.
Fitness and virulence in BHK21 cells for selected mutantsa
| Characteristic | Reference clone | U1323A mutant | U2617G/A3802G double mutant |
|---|---|---|---|
| Fitness | |||
| Relative fitnessb | 1.00 ± 0.001 | 0.429 ± 0.024 | 1.17 ± 0.03 |
| Lag time, L (h) | 4.54 ± 0.09 | 7.44 ± 0.37 | 4.77 ± 0.25 |
| Exponential growth rate, r (h−1) | 1.05 ± 0.03 | 0.890 ± 0.040 | 1.23 ± 0.14 |
| Viral yield per cell, K (PFU) | 2,189 ± 574 | 289 ± 75 | 840 ± 194 |
| Length of cell infection cycle, τ (h) | 7.21 ± 0.14 | 6.21 ± 0.11 | 5.58 ± 0.43 |
| Virulence | |||
| Relative cytotoxicityb | 1.00 ± 0.05 | 1.15 ± 0.02 | 0.925 ± 0.034 |
| Viability of infected cells (%) | 72.6 ± 1.7 | 72.5 ± 3.2 | 69.4 ± 2.1 |
a
Mean values ± SEM from five (fitness and growth curves), eight (relative cytotoxicity), and three (cell viability) replicate assays.
b
Values from Table 1.