Iminosugars in combination with interferon and ribavirin permanently eradicate noncytopathic bovine viral diarrhea virus from persistently infected cells.

We evaluated interferon (IFN) and ribavirin (RBV) as dual therapy and as part of triple-combination therapies with the iminosugars N-butyl-deoxynojirimycin (NB-DNJ), N-nonyl-deoxynojirimycin, and N-7-oxanonyl-6-deoxymethyl-galactonojirimycin. The ability of these compounds to clear bovine viral diarrhea virus (BVDV), a surrogate model for hepatitis C virus (HCV), from a persistently infected Madin-Darby bovine kidney cells cell line was determined by monitoring the secretion of viral RNA and the infectivity of secreted virions. In the BVDV system, after treatment with IFN-RBV alone, viral rebound was observed immediately after removal of the drugs. In contrast, we demonstrate that a triple drug combination of IFN, RBV, and an iminosugar eradicated the BVDV infection in a time- and a dose-dependent manner, leading to sustained viral clearance. Importantly, in the case of NB-DNJ, the sustained viral clearance was achieved by using physiologically relevant and tolerated drug concentrations. Therefore, the use of a triple-combination therapy that includes an iminosugar may prove to be of greater therapeutic value for the treatment of HCV infection than the use of IFN-RBV alone.