FIG. 7.

PCR analysis of proviral sequences in blood samples from sheep inoculated with BLV-infected B cells. Blood was collected weekly following the injection of 10⁷ BLV-infected or control B cells. Proviral sequences were amplified with BLV tax primers and analyzed by Southern blot hybridization with a ³²P-labeled full-length BLV probe. BLV sequences were detected in blood samples collected 3 weeks p.i. from sheep injected with the following FLK-exposed B cell types (one animal per cell type): 24- and 96-h cultures of short-term iPfB cells (iPfB 24h BLV and iPfB 96h BLV); 8- and 14-day cultures of cytokine/CD154 iPfB cells (iPfB 8d BLV and iPfB 14d BLV); blood-derived B cells cultured for 60 days (BL-2); and 48-day cultures of jPfB clone 2 and clone 4 B cells (jPfB Clone2 BLV and jPfB Clone4 BLV). Control lane, sheep injected with OVK-exposed cytokine/CD154 14d iPfB cells (14d cntl).