Table 1.
The NA activities of H6 reassortant viruses containing different NA
| H6 reassortants | ||||
|---|---|---|---|---|
| Source of the NA gene (subtype) | Abbrev. | HA titer | Virus titer (log10PFU/ml) |
NA activity1 |
| A/New Caledonia/20/99 (H1N1) | NC99 | 1024 | 9.1 | 149 |
| A/South Dakota/6/07 (H1N1) | SD07 | 1024 | 9.0 | 126 |
| A/California/7/09 (pH1N1) | CA09 | 1024 | 8.6 | 263 |
| A/HongKong/213/03 (H5N1) | HK03 | 1024 | 8.7 | 296 |
| A/Panama/2007/99 (H3N2) | Pan99 | 1024 | 9.0 | 79 |
| A/California/07/04 (H3N2) | CA04 | 1024 | 9.1 | 97 |
| A/Uruguay/716/07 (H3N2) | Uru07 | 1024 | 8.9 | 75 |
Each virus was adjusted to HA titer of 1024 and virus titer was determined by plaque assay. NA activity was determined by the miniaturized colorimetric assay using fetuin substrate.
1
NA activity was defined as the reciprocal of virus dilution at which the OD550 value is 1.0. The values are the average of two independent experiments.