Abstract
We have developed a West Nile virus (WNV) subgenomic replicon harboring the secreted alkaline phosphatase (SEAP) reporter gene instead of viral structural genes (designated repWNV/SEAP). The repWNV/SEAP allowed easy evaluation of viral replication efficiency by direct measurement of SEAP secretion of the cell culture medium in physical containment level 2 facilities. Furthermore, we validated the availability of this system using the known anti-flavivirus gene, mouse oligoadenylate synthetase 1b (Oas1b). The Oas1b-transfected cells were more resistant to repWNV/SEAP replication than were the original cells. Thus, not only this system affords a useful tool for the identification/evaluation of anti-flavivirus genes/drugs in terms of safety, ease of use and reliability, but should be able to reduce or replace the bioassay using laboratory animals.
