Figure 4.

(Top) GFP production in cells incubated with supernatants from induced 293 cell lines carrying the TR-less B95.8/F factor DNA. Supernatant (0.5 ml) from p2124 encapsidated in the TR⁻2/293 cell line was mixed with 10⁵ Raji cells in 0.5 ml culture medium. About 3% of the cells were GFP-positive, indicating a virus titer of at least 6 × 10³ infectious viruses per ml. GFP fluorescence was investigated 48 h after infection. (Middle) Corresponding phase-contrast light microscopy. (Bottom) Production of the VCA in TR⁻2/293 after induction of the lytic cycle. Fixed cells were incubated with a mAb against VCA and a second anti-mouse antibody coupled to the Cy5 fluorochrome. Stained cells were visualized in UV light.