6). The analysis by plaque assay was again in agreement with qRT-PCR (data not shown).Figure selleck kinase inhibitor 5Action of chloroquine added at 24-hour intervals on DENV-2 replication in Vero cells. The viral RNA present in the culture supernatants of Vero cells infected with DENV-2, both untreated and treated chloroquine (every 24 hours after infection), was extracted …Figure 6Action of chloroquine added at 12-hour intervals on DENV-2 replication in Vero cells. The viral RNA present in the culture supernatants of Vero cells infected with DENV-2, both untreated and treated chloroquine (every 12 hours after infection), was extracted … Viral replication in Vero-infected cells was impaired by the addition of CLQ at 1 hour after infection and at 12-hour intervals after infection.

With this approach, both the plaque assay and qRT-PCR showed a statistically significant reduction in viral yield similar to obtained for cells exposed to CLQ at 24-hour intervals.4. Discussion We report here data showing that CLQ is an effective antiviral agent for DENV-2 under cell culture condition. The inhibitory effect was observed when the drug was added 1h after the initiation of infection, probably due to the increase of the endosomes pH and thus subverting the ongoing fusion events between virus envelope and endosome membranes. These results suggest that CLQ could have a potential for therapeutic use against dengue virus and even against other viruses that penetrate cells by endocytosis. In that sense, some studies have shown that CLQ inhibits SARS coronavirus (SARS-CoV) replication in vitro [6, 7].

In addition, di Trani et al. [8] tested the antiviral effects of CLQ in vitro against selected human and avian viruses belonging to different subtypes and displaying different pH requirements. Those authors found that CLQ had inhibitory effect against the viruses when the drug had been added at the time of infection and the effect was lost after 2-hour postinfection. Finally, Eng et al. [9] reported that CLQ is able to inhibit influenza A virus replication in vitro. CLQ is a safe drug with over half a century of use in the treatment of malaria; therefore, the implementation of a protocol to use it in dengue treatment would not be a problem. Since there is a correlation between high viral load and development of DHF/DSS [10], the use of CLQ to treat dengue virus infection as soon as the patients present the dengue symptoms could prevent the development of the severe forms of the disease Brefeldin_A due to the reduction of dengue viremia. Furthermore, due to its interference with TNF-�� cytotoxicity [11], CLQ would probably reduce the inflammatory symptoms, such as high fever and backache, associated with dengue.