FIG. 7.

Efficiency of [³H]choline release from pulse-chase labeled cells (membrane lysis) at different pH values by Ad5/35 vectors with different fiber shaft lengths (A) and following exposure to HD5/35 and Δ5/35 vectors (B). In panel A, cells were labeled with [³H]choline and exposed to equal doses of viruses at various pH levels as described in Materials and Methods. The amount of [³H]choline released from cells was quantified by a scintillation counter. Note that the Ad5/35 vector with a short fiber shaft (Ad5/35S) permeabilized cells less efficiently than its long-shafted counterpart (Ad5/35L). In panel B, [³H]choline-labeled cells were exposed to equal doses of Ad vectors, and the virus cell permeabilizing activity was analyzed at pH 5.5. Control, percentage of the total cell radioactivity released after incubation with different pH buffers only. n = 4.