TABLE 4.
In vitro and in vivo characteristics of the reverse-genetic viruses
| Virus | Glycosylation | Cleavage site sequence | ECEa
|
PFU/ml in CEF cells
|
Intravenous pathotyping in chickens
|
|||||
|---|---|---|---|---|---|---|---|---|---|---|
| EID50/ml | MDTb | Trypsin | No trypsin | Morbidityc | Mortalityd | Virus titere | Hi titerf | |||
| Parent | NST (+) | PQ——RKKR | 9.7 | >5 | 8 × 109 | none | 1/10 | 0/0 | 5.8 ± 0.4 | 8.2 ± 0.6 |
| rg1 | NST (+) | PQ——RKKR | 8.9 | >5 | 1 × 109 | none | 0/10 | 0/10 | 1.5 ± 2.5 | 4.7 ± 1.4 |
| rg2 | NSK (−) | PQ——RKKR | 9.2 | >5 | 3 × 108 | none | NDg | ND | ND | ND |
| rg3 | KST (−) | PQ——RKKR | 10.5 | >5 | 4 × 108 | none | 0/10 | 0/0 | <1.0 | 2.1 ± 1.8 |
| rg4 | NST (+) | PQ—RRKKR | 9.2 | 3.6 | 2 × 109 | none | 0/10 | 0/0 | <1.0 | 5.2 ± 1.0 |
| rg5 | NST (+) | PQRKRKKR | 10.9 | 2.2 | 4 × 107 | 1 × 106 | 10/10 | 1/10 | 3.3 ± 1.4 | 6.8 ± 0.7 |
| rg6-CK/Scot/59 H5 | KST (−) | PQ——RKKR | 10.5 | 2.2 | 3 × 107 | 3 × 105 | 10/10 | 3/10 | 2.5 ± 0.1 | 6.0 ± 1.3 |
a
The challenge doses were adjusted to 104 EID50/0.2 ml and 106 EID50/0.2 ml for the pathogenicity test in ECE and chickens, respectively.
b
MDT, average number of days required to kill the inoculated eggs.
c
Number of birds that manifested clinical signs/number of birds inoculated.
d
Number of birds that died/number of birds inoculated.
e
The mean virus titer of three samples is expressed as the log10 EID50 per milliliter ± standard deviation.
f
Log2 hemagglutination inhibition titer (mean titer of sera collected from the surviving birds 10 days after challenge) ± standard deviation.
g
ND, test not done.