FIG. 2.

Inhibitors of endosomal acidification block the entry of RRV into RFs. (A to C) RFs were infected with RRV-luciferase in the presence of different concentrations of bafilomycin A1 (A), monensin (B), or NH₄Cl (C). Luciferase activities in the culture supernatants were monitored at the indicated time points and compared with those for control cells infected with RRV-luciferase in parallel without inhibitor treatment. (D) Inhibitors of endosomal acidification blocked the entry of Alexa Fluor 488-transferrin into RFs. (E) Inhibitors of endosomal acidification had no effect on cell viability. RFs were treated with inhibitors of endosomal acidification under the conditions used for the virus infection assay and were evaluated for viability by staining with PI and DAPI. Cells left without medium and CO₂ for 1 h were used as positive controls.