Figure 3.

Modulation of infectivity of VSV₂₉₃-FVIII. Viral vector producer cells were grown in the presence (+) or absence (−) of tetracycline (Tet) to repress or induce VSV-G expression, respectively, and were incubated with (+) or without (−) neutralizing VSV-G-specific mAb before transduction of COS-7 cells in vitro or injection in FVIII-deficient neonates. FVIII activity was determined in the 24-hr conditioned medium of the transduced COS-7 cells, and the relative transduction efficiencies were determined by FVIII-specific PCR (B, lanes 2–5). PCR also was performed on DNA from liver (lane 7), spleen (lane 8), and lungs (lane 9) of FVIII-deficient recipient mice injected with the same inactivated concentrated vector preparations. Positive control derived from FVIII-containing cells (lane 10) and molecular weight marker corresponding to the Smart Ladder (lanes 1 and 6) (Eurogentec, Liège, Belgium) are included, and FVIII (1.1 kb)-specific fragments are indicated.