FIG. 5.

Correlation of spontaneous inactivation with the inhibition of VSV-G by NH₄Cl. To determine the effect of the duration of infection on inhibition by NH₄Cl, cells were preincubated in medium containing NH₄Cl and infected with G1nβgSvNa(VSV-G) in the presence of NH₄Cl after different times of preincubation as described for Fig. 3. The data represent the mean and SEM of 9 to 15 determinations at each time in two to four separate experiments. For thermal stability, G1nβgSvNa(VSV-G) was incubated in a water bath at 37°C in the presence of NH₄Cl. Aliquots of the virus mixture were removed at 0, 2, and 4 h and assayed for transduction activity as described in Materials and Methods. Mean transduction titers obtained after 0-h incubation were considered to be 100%, and percent transduction after 2 and 4 h was calculated relative to the mean titers obtained at 0 h. Each value represents the mean and SEM of six determinations at each time in two separate experiments.