FIG. 3.

β-l-Fd4C inhibits viral DNA synthesis in primary duck hepatocyte cultures. (A) Primary duck hepatocyte cultures were inoculated with an infectious serum on day 1 postseeding, and intracellular viral DNA was analyzed after Southern blotting and specific hybridization at the indicated time points during cell culture. β-l-Fd4C and 3TC were added 6 days postinoculation (day 7), at the indicated concentrations, for 6 consecutive days with a daily medium change in the curative protocol. In this experiment, viral DNA was analyzed at the end of treatment (day 13) and 4 days posttreatment (day 17). (B) In the preventive treatment, cultures were inoculated with an infectious serum 2 days postplating. Drugs (β-l-Fd4C and 3TC) were added 1 day prior to the inoculation and were maintained at the indicated concentrations for 4 days postinoculation. In this experiment, viral DNA was analyzed at the end of treatment (day 6), and 3 and 8 days posttreatment (days 9 and 14, respectively). The viral replicative intermediates are indicated.