Niclosamide treatment neither hinders the endocytosis of DENV nor enhances IFN-β production.

(A) LDH assay showing cytotoxicity in niclosamide (Niclo)-treated Neuro-2a cells for 48 h with various concentrations. (B) Representative Western blot showing viral NS3 protein expression in DENV2 (MOI = 1)-infected Neuro-2a cells for 48 h with or without niclosamide (Niclo) pretreatment. β-actin served as the internal control. The relative ratios of the measured proteins compared to β-actin are also shown. Confocal microscopy (C) and flow cytometry (D) were used to measure the positive Neuro-2a cells carrying Alexa-594 labeled (red) DENV2 (MOI = 1) 2 h post-infection in the presence of niclosamide (Niclo). E: ELISA analysis showing IFN-β production in DENV2 (MOI = 1)-infected A549 cells for 48 h with or without niclosamide (Niclo) pretreatment. DMSO was used as a solvent control. The quantitative data are depicted as the mean ± SD of three independent experiments. ** P 0.01. ns, not significant.