TABLE 1.
Kinetics of vector titers upon serial passages in permissive CRFK cells
| Vector | Titer at no. of vector passages givena:
|
||||||
|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | |
| pCF-7 | 2.0 × 106 | 3.0 × 107 | 6.0 × 106 | 6.0 × 107 | 3.0 × 106 | 1.0 × 107 | 5.0 × 106 |
| pCF-FCV14 | 5.0 × 105 | 3.0 × 104 | 6.0 × 104 | — | — | — | — |
| pCF-FCV14-U3 | 3.0 × 105 | 1.8 × 105 | 5.0 × 105 | — | — | — | — |
| pCF-FCV23 | 3.5 × 106 | 1.2 × 107 | 5.5 × 106 | 1.3 × 107 | 9.0 × 106 | 4.0 × 106 | 6.5 × 106 |
| pCF-FCV23-U3 | 3.0 × 106 | 2.0 × 107 | 6.0 × 106 | 2.4 × 107 | 3.0 × 107 | 4.0 × 106 | 6.5 × 106 |
| pCF-FCV24 | 2.0 × 106 | 2.5 × 107 | 5.5 × 106 | 1.7 × 107 | 4.0 × 106 | 2.5 × 106 | 3.0 × 106 |
| pCF-FCV24-U3 | 1.5 × 106 | 6.0 × 106 | 2.0 × 106 | 5.5 × 106 | 4.5 × 106 | 2.5 × 106 | 5.0 × 106 |
a
Vector titers were determined with FFV-FAB cells as described in Materials and Methods. The titers are the mean value of two independent vectors each, except for vectors pCF-7 and pCF-FCV14, for which only one clone was used. —, culture was no longer analyzed.