Blockade of dengue virus entry into myeloid cells by endocytic inhibitors in the presence or absence of antibodies

CARRO AC; PICCINI LE; DAMONTE EB

PLOS NEGLECTED TROPICAL DISEASES

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2018 vol. 12 p. 1 - 18

1935-2735

BackgroundDengue is the most prevalent arthropode-borne viral human disease in tropical and subtropical regions, caused by four dengue virus (DENV) serotypes. In spite of the increasing global incidence, no specific antiviral therapy is available. Cells of the mononuclear phagocyte lineage are the main targets either for primary or secondary antibody (Ab)-mediated human DENV infection, usually associated to severe forms of disease. Since virus entry may be a convenient therapeutic alternative, this study aimed to investigate the mode of DENV internalization myeloid cells in the absence and presence of DENV Ab and evaluate the inhibitory activity of diverse biochemical inhibitors of endocytosis.Methodology/Principal FindingsBy infectivity assays and quantitative RT-PCR determinations, it was demonstrated that DENV-2 entry into U937 and K562 cells in the absence of Ab was highly inhibited by early treatment with ammonium chloride, chlorpromazine and dynasore, but it was not affected by methyl-β-cyclodextrin, indicating that DENV-2 utilizes a low pH-dependent, clathrin- and dynamin-mediated endocytic infectious pathway for the primary entry into both human myeloid cells. To study the Ab-mediated entry of DENV, the experimental conditions for enhancement of infection were established by inoculating immune complexes formed with DENV-2 and the Ab 2H2 or 3H5. The internalization of DENV-2-2H2 or DENV-2-3H5 complexes in both myeloid cells was also dependent on acid pH and dynamin but a differential requirement of clathrin-mediated endocytic route was observed depending on the FcR involved in complex uptake: the infection through FcRII was dependent on clathrin-coated vesicles whereas theinternalization pathway mediated by FcRI was independent of clathrin. This property was not serotype-specific. Conclusions/SignificanceDENV entry into myeloid cells in the absence or presence of Ab can be blocked by diverse biochemical inhibitors affecting cellular factors involved in endocytosis. The identification of virus-host interactions involved in virus penetration may allow the finding of host-targeted antivirals widely active against diverse pathogenic flaviviruses with similar requirements for virus entry.