FIG 14.

HCMV infection is impaired when endosomal acidification is blocked. (A) HS-578T cells were pretreated with NH₄Cl (50 mM) at 37°C for 60 min, followed by infection for 5.5 h. RNA was extracted, and HCMV UL123 expression was monitored by RT-qPCR and normalized against GAPDH amplified in the same reaction. (B) HS-578T cells were treated with NH₄Cl at various concentrations. HCMV infection was carried out for 4.5 h, and the cells were washed with low-acid buffer for 3 min to inactivate uninternalized virus and cultured for additional 3 days without NH₄Cl before FACS analysis. (C) Cell viability was monitored by CytoTox-One assay using the highest dose (100 mM) of NH₄Cl. (D and E) HS-578T cells (D) and MRC-5 cells (E) were pretreated with NH₄Cl (50 mM), monensin (25 nM), or bafilomycin A1 (BFLA1) (200 nM). Representative data from 3 independent experiments for each cell type are shown (P < 0.0001 for both NH₄Cl and monensin versus solvent control; P < 0.01 for bafilomycin A1 versus solvent control).