TABLE 1.
Infectivity and growth characteristics of HA receptor binding site mutants
| Mutation | Binding (% WT level)a | HA titer (turkey RBCsb) | Titer in MDCK cells (log10 PFU/ml) | Lung viral titer (log10 PFU/ml) on day 3c |
|---|---|---|---|---|
| None | 100 | 256 | 7.0 | 6.3 |
| Y98F | 5 | <2 | 7.0 | 3.4 |
| S136T | 45 | 128a | 6.8 | 6.6 |
| S225D | 53 | 512a | 6.8 | 6.1 |
| S228G | 112 | 512a | 7.0 | 6.1 |
| W222R | 64 | 5.6 | 6.7 | |
| K238N | 512 | 6.6 | 5.2 |
a
Results from reference 18.
b
RBCs, red blood cells.
c
Mice were infected i.n. with 106 PFU of WT or mutant H3N1 viruses generated as described previously (18) or with 7 × 103 PFU for the experiment with pseudorevertant viruses. Lungs from three mice per group were collected and pooled, and titers were determined on MDCK cells.