TABLE 1.
Constructs transfected to generate VLPsa
| Plasmid | Amt (μg) of construct used
|
|||
|---|---|---|---|---|
| WT | A21/B/NEP | delNES/NEP | −NEP | |
| pCAGGS-B/Yamagata/73/PB1 | 1 | 1 | 1 | 1 |
| pCAGGS-B/Yamagata/73/PB2 | 1 | 1 | 1 | 1 |
| pCAGGS-B/Yamagata/73/PA | 1 | 1 | 1 | 1 |
| pCAGGS-B/Lee/40/HA | 1 | 1 | 1 | 1 |
| pCAGGS-B/Lee/73/NP | 1 | 1 | 1 | 1 |
| pCAGGS-B/Yamagata/73/NANB | 1 | 1 | 1 | 1 |
| pCAGGS-B/Yamagata/73/M1 | 1 | 1 | 1 | 1 |
| pCAGGS-B/Yamagata/73/BM2 | 1 | 1 | 1 | 1 |
| pCAGGS-B/Yamagata/73/NS1 | 1 | 1 | 1 | 1 |
| pCAGGS-B/Lee/40/NEP | 1 | 0 | 0 | 0 |
| pCAGGS-A21/B/NEP | 0 | 1 | 0 | 0 |
| pCAGGS-B/delNES/NEP | 0 | 0 | 1 | 0 |
| pPOLI-B/Lee/NSCAT | 1 | 1 | 1 | 1 |
Eukaryotic expression plasmids were constructed for the influenza B virus gene products and used to generate VLPs after transfection into 293T cells. WT, the plasmids corresponding to the complete set of plasmids representing the entire set of influenza B virus gene products, including a viral RNA-like CAT gene. A21/B/NEP replaces the wild-type NEP with the construct pCAGGS-A21/B/NEP. In the column labeled delNES/NEP, wild-type NEP is replaced with a mutant version of NEP lacking the first 20 aa. −NEP, the complete set without the plasmid encoding the NEP protein from influenza B virus. In all cases 1 μg per plasmid was transfected for a total of 10 or 11 μg (−NEP or others, respectively). Supernatants of transfected cells showed HA titers of log 25 in repeated experiments.