FIG. 9.

Infectivity of virus particles within cytoplasmic organelles is dependent on an acidic environment. HuH7 cells were infected with the HSV-1 strain tsProt.A, acid washed, and then incubated at 39°C for 7 h. Cycloheximide (20 μg/ml) was added 30 min prior to downshift to 31°C. At the time of downshift, cells received 150 μM chloroquine or 200 nM bafilomycin A1 or no treatment as shown in Fig. 7A. Cells were then incubated at 31°C for 9 h. PNSs were subjected to sucrose gradient centrifugation and fractionated. (A) PFU titrations of gradient fractions from untreated cells (light gray bars) and cells treated with chloroquine (dark gray bars) or bafilomycin A1 (open bars). (B) Assay for enveloped virions present in untreated cells and cells treated with chloroquine or bafilomycin A1 (indicated as in A). All values plotted are means of duplicate samples, and error bars indicate the range from the mean.