Table 2

Kinetics of virus production after plasmid transfection into 293T cells

Hours after plasmid transfectionVirus titers in culture supernatant, pfu/ml
Experiment
1234
1200ND0
1803  ×  10 ND0
242  ×  1028  ×  1032  ×  1036  ×  103
304  ×  1031  ×  1055  ×  1049  ×  104
365  ×  1042  ×  106>1  ×  1057  ×  105
429  ×  1051  ×  107>1  ×  1065  ×  106
487  ×  1065  ×  107>1  ×  1061  ×  107
  • 293T cells were transfected with eight RNA polymerase I plasmids encoding A/WSN/33 virus genes (Experiments 1 and 2) or with these plasmids except the PB1 gene, which was derived from A/PR/8/34 virus (Experiments 3 and 4), and only PA, PB1, PB2, and NP (Experiment 1) or nine (Experiments 2–4) protein expression plasmids as described in the text. At different time points, we titrated virus in the culture supernatant in MDCK cells. ND, not determined.