Brefeldin A and Cytochalasin B reduce dengue virus replication in cell cultures but do not protect mice against viral challenge

Background. Dengue is an emerging arboviral disease caused by dengue virus (DENV). DENV belongs to the family Flaviviridae and genus Flavivirus. No specific anti-DENV drugs are currently available. Methods. We investigated the antiviral activity of Brefeldin A (BFA) and Cytochalasin B (CB) against this infection. The drugs BFA and CB were used in the in vitro treatment of dengue-2 virus (DENV-2) infections in Vero cell cultures and in protection from lethality by post-challenge administration in Swiss mice. Viral load was quantified by qRT-PCR and plaque assay in Vero cell cultures, post-infection, treated or not with the drugs. Post-challenge drug levels were evaluated by survival analysis. Results. Our results indicate that doses of 5 µg ml−1 of BFA and 10 µg ml−1 of CB are not toxic to the cells and induce a statistically significant inhibition of DENV-2 replication in Vero cells when compared to control. No BFA- or CB-treated mice survived the challenge with DENV-2. Conclusion. These data suggest that BFA and CB have an antiviral action against DENV-2 replication in Vero cell culture, but do not alter infected mice mortality.