TABLE 2.
Virulence scores from the six different assays with parental rBC and rGBT and their chimeric viruses
| Swap | Virulence scorea |
|||||
|---|---|---|---|---|---|---|
| In vitro replication | Plaque size | Fusion index | ICPI | In vivo replication | Clinical signs/mortality | |
| rBC derivatives, rGBT envelope-associated protein genes | ||||||
| M | Ø | Ø | Ø | Ø | Ø | - |
| F | +++ | +++ | +++ | +++ | +++ | +++ |
| HN | Ø | + | + | + | Ø | - |
| F+HN | +++ | ++ | +++ | +++ | +++ | +++ |
| M+F+HN | ++ | ++++ | ++++ | +++ | ++ | ++ |
| rGBT derivatives, rBC envelope-associated protein genes | ||||||
| M | Ø | --- | Ø | - | Ø | Ø |
| F | --- | - | --- | --- | --- | --- |
| HN | Ø | ++ | Ø | Ø | Ø | Ø |
| F+HN | --- | --- | --- | -- | -- | --- |
| M+F+HN | --- | --- | ---- | -- | --- | - |
| rBC derivatives, rGBT polymerase-associated protein genes | ||||||
| N | Ø | --- | ND | Ø | Ø | - |
| P | Ø | -- | ND | Ø | Ø | - |
| L | + | -- | ND | ++ | ++ | +++ |
| N+P+L | ++ | +++ | ND | ++ | +++ | ++ |
| Tr | Ø | Ø | ND | Ø | Ø | Ø |
| rGBT derivatives, rBC polymerase-associated protein genes | ||||||
| N | - | - | ND | Ø | Ø | Ø |
| P | - | Ø | ND | Ø | Ø | Ø |
| L | -- | --- | ND | -- | -- | -- |
| N+P+L | --- | ---- | ND | -- | --- | --- |
| Tr | -- | Ø | ND | Ø | Ø | Ø |
a
Increases and decreases in virulence relative to the respective parent are indicated as + and - symbols, respectively. The scoring is for a descriptive comparison and was not intended to be quantitative. ND, not determined; Ø, no observable effect.