We detected a large number of IFN response genes induced in both cell line infections and in dengue patients (see Figure 3C ). In our study, viperin was one of the most highly upregulated genes in the type I IFN response pathway. Viperin has previously been identified as an IFN-induced anti-viral protein in HCMV and HCV infection [26, 27] . In order to investigate the role of viperin in dengue infection, we used an established A549 cell line stably overexpressing viperin (Vip) [26] . Comparing to infection in wild type A549 cells (WT), viperin overexpressing cells were significantly resistant to viral replication, as shown by plaque assay two days after infection ( Figure 5A ), with and without pre-treatment with IFNb (+IFN; 500 U/ml). Although pre-treatment with IFNb had the greater anti-viral effect, viperin over expression alone resulted in a small, but significant, reduction in virus production both with (P = 0.038) and without (P = 0.0004) IFNb pretreatment. These results suggest that viperin is an functional component of the IFN-mediated response to dengue, and demonstrate, for the first time, that viperin could be part of the anti-dengue response.