TABLE 1.
Properties of pH1N1 LAIV viruses
| Property | PAWT+ NSWT− virus | PAMUT− NSWT− virus | PAWT+ NS1MUT+ virus | PAMUT− NS1MUT+ virus |
|---|---|---|---|---|
| Inhibition of host gene expressiona | + − | − − | + + | − + |
| Viral replication in vitro | High | Low | Low | High |
| MLD50 (PFU/mouse)b | 681 | 68,129 | >105 | 2,371 |
| Viral replication in mouse lungs | High | Low | Low | High |
| Induction of innate immune response in mice | + | − | − | + |
| Induction of adaptive immune response in mice | + | − | − | + |
a
PA (left) and NS1 (right) proteins with (+) or without (−) the ability to inhibit host gene expression.
b
Mortality was determined over 2 weeks (n = 5).