IFNG and infection: IFN-γ has been shown to upregulate and activate cellular and humoral immunity,25,26 but it can also be directly antiviral versus YFV in many cell types through upregulation of genes that encode antiviral effector proteins such as IFN-stimulated genes (ISGs).27 Since IFN-γ inhibition of 17D-204 occurs at early times after infection of AGB6 mice, we attempted to determine if differences in tissue-specific expression of IFN-γ or ISGs could be detected in the absence of IFN-γ.