FIG. 3.

Inhibition of transduction by RRV E2E1-pseudotyped retrovirus by lysosomotropic weak bases. NIH 3T3 cells were treated for 1 h with the indicated concentrations of (A) chloroquine or (B) ammonium chloride in PBS. Medium carrying pseudotyped nlslacZ-conveying retroviruses (RRV glycoproteins, Mo-MuLV virus envelope protein, or VSV G protein) containing the indicated concentration of base as well as hexadimethrine bromide (8 μg/ml) was incubated with the cells in a CO₂ incubator at 37°C. The cells were stained with X-gal at 48 h postinfection, and blue cells were counted. Viral transduction of cells treated with the indicated concentrations of reagent is represented as a percentage of the level of transduction of untreated cells. The data are representative of three independent experiments.