TABLE 3.
Lack of plasminogen-mediated growth of a mutant WSN virus possessing the glycosylation site at position 130 in the NAa
| Virus | Reciprocal of HA titer in culture supernatant
|
|||
|---|---|---|---|---|
| Plasminogen (μg/ml)
|
Trypsin (0.5 μg/ml) | |||
| 50 | 5 | 0.5 | ||
| Wild-type WSN | >2,048 | >2,048 | >2,048 | >2,048 |
| WSN-146N | <b | < | < | 1,024 |
| WSN-453R | < | < | < | 1,024 |
| WSN-453L | < | < | < | 1,024 |
a
Viral growth was measured by determining the HA titer in the culture supernatant. A negative control, for which protease was not added to culture medium, was run in each case; virus was never detected in undiluted culture supernatant.
b
<, virus was not detected in undiluted culture supernatant.