CONICET | Buscador de Institutos y Recursos Humanos

Dengue virus (DENV) is an arthropod-borne member of Flaviviridae that can cause in the man a feverish and self-limited disease, the dengue fever, or the more severe and potentially lethal forms of dengue hemorrhagic fever/dengue shock syndrome. Currently there are no available vaccines or antiviral therapies. Due to the co-circulation of the four DENV serotypes (DENV-1 to 4) in the same regions and the chance of heterologous antibody-dependent enhancement of the infection, any therapeutic or preventive development must be protective against all serotypes. Otherwise, the knowledge of the viral multiplication cycle is critical for the finding of potential antiviral targets. In this field, the initial steps leading to DENV entry into the host cell, at present poorly understood, represent an interesting antiviral strategy. Here, the mode of entry of DENV-3 to mammalian cells was studied by analyzing the effect of pharmacological inhibitors of different endocytic pathways on virus infectivity and antigen expression in monkey Vero and human A549 cells. DENV-3 entry into both cells was strongly inhibited by treatment with ammonium chloride or concanamycin A, two inhibitors of endocytosis which raise the endosomal pH. The presence of inhibitors of clathrin-mediated endocytosis, chlorpromazine or dansylcadaverine, did not affect virus entry whereas dynasore reduced DENV-3 internalization, indicating the involvement of dynamin in entry. A slight effect on virus infection was produced by nystatin and methyl-β-cyclodextrin, two cholesterol-binding agents. Then, our results provide evidence that DENV-3 enters into Vero and A549 cells by a low pH-mediated, clathrin-independent endocytosis route, dependent on dynamin. Furthermore, the comparison with our previous studies with DENV-1 and DENV-2 confirms that diverse viral and cellular factors affect DENV entry and should be considered for evaluation of safe antiviral agents reactive against all DENV serotypes.