The dengue virus non-structural protein 1 (NS1) is secreted efficiently from infected mosquito cells

Dengue virus NS1 is a glycoprotein of 46-50 kDa which associates as a dimer to internal and cytoplasmic membranes and is also secreted, as a hexamer, to the extracellular milieu. However, the notion exist that NSI is secreted only from infected vertebrate and not mosquito cells. In this work, evidence is presented showing that NSI is secreted efficiently by infected mosquito cells. NS1 was detected in cell supernatants starting at 6 hpi with a continuous concentration increase up to 24 hpi. Nevertheless, cell viability showed an average cell survival of 97%. At variance with observations with vertebrate cells, NS1 does not seems to associate with the cytoplasmic membrane of insect cells. Finally, evidence is presented indicating that NSI is secreted from insect cells as a barrel-shaped hexamer. These findings provide new insights into the biology of NSI and open questions about the role of secreted NSI in the vector mosquito. (C) 2015 Elsevier Inc. All rights reserved.