Table 1.
Replication and virulence of recombinant parental and reassortant Sw/1130 viruses in mice
| Recombinant virusa | Stock titer (TCID50/ml) | Lung viral titer (SD)b |
MLD50c | |
|---|---|---|---|---|
| 3 days p.i. | 5 days p.i. | |||
| Sw/1130 | 2.0 × 106 | 2.2 (0.2) | 1.7 (0.1) | >6 |
| CT-Sw/1204HA | 1.0 × 107 | 3.9 (0.3)d | 3.5 (0.3)d | 4.9 |
| CT-Sw/1204NA | 2.0 × 106 | 2.4 (0.2) | 2.1 (0.2) | >6 |
| CT-Sw/1204PB2 | 1.0 × 107 | 3.6 (0.2)d | 3.4 (0.3)e | 5.1 |
| CT-Sw/1204PB1 | 1.0 × 106 | 1.9 (0.1) | - | >6 |
| CT-Sw/1204PA | 4.0 × 106 | 3.7 (0.3)e | 4.2 (0.4)e | 5.3 |
| CT-Sw/1204NP | 2.0 × 106 | 2.7 (0.2)e | 2.8 (0.2)e | 5.5 |
| CT-Sw/1204M | 2.0 × 106 | 2.2 (0.2) | 2.1 (0.2) | >6 |
| CT-Sw/1204NS | 6.3 × 106 | 2.4 (0.2) | 3.0 (0.3) | 5.5 |
| CT-Sw/1204HA-NA | 4.0 × 107 | 3.7 (0.3)d | 3.7 (0.3)d | 4.5 |
| CT-Sw/12043P | 1.0 × 107 | 4.9 (0.4)d | 3.7 (0.3)e | 4.7 |
| CT-Sw/1204vRNP | 2.0 × 107 | 4.9 (0.5)d | 3.9 (0.3)e | 4.7 |
| CT-Sw/1204 | 3.2 × 108 | 5.9 (0.5)d | 5.2 (0.4)e | 3.5 |
Reassortant virus names were assigned according to the origin of the exchanged genes (e.g., CT-Sw/1204HA denotes a reassortant bearing the HA of CT-Sw/1204 with the rest of its genes from Sw/1130). Parental strains are in boldface.
Obtained from mice inoculated intranasally with 104 TCID50 of the indicated virus; titers are expressed as log10 TCID50/g. The dash denotes negative detection (<1.5 log10 TCID50/g).
Determined by inoculating mice with 102 to 106 TCID50 of virus and expressed as the log10 TCID50 required to yield 1 LD50.
P < 0.005 comparing virus titers relative to Sw/1130-inoculated mice (two-tailed unpaired t test).
P < 0.05 comparing virus titers relative to Sw/1130-inoculated mice (two-tailed unpaired t test).