Chloroquine interferes with dengue-2 virus replication in U937 cells

The objective of this study was to investigate the use of chloroquine (CLQ) as an antiviral agent against dengue. Chloroquine, an amine acidotropic drug known to affect intracellular exocytic pathways by increasing endosomal pH, was used in the in vitro treatment of U937 cells infected with dengue virus type 2 (DENV-2). Viral replication was assessed by quantification of virus produced through detection of copy numbers of DENV-2 RNA, plaque assay and indirect immunofluorescence. qRT-PCR and plaque assays were used to quantify the DENV-2 load in infected U937 cells after CLQ treatment. It was found that a dose of 50mg/mL of CLQ was not toxic to the cells and resulted in significantly less virus production in infected U937 cells than occurred in untreated cells. In the present work, CLQ was effective against DENV-2 replication in U937 cells, and also caused a statistically significant reduction in expression of proinflammatory cytokines. The present study indicates that CLQ may be used to reduce viral yield in U937 cells.