Expression of gp100 in melanoma metastases resected before or after treatment with IFN alpha and IL-2

To determine whether the interferon-induced 9-27 protein of human cells contributes to the antiviral state, we expressed the 9-27 cDNA under the control of a constitutive promoter and assayed transfected cells for enhanced virus resistance. The intracellular distribution of 9-27 resembled that of cytoskeleton-associated proteins. Analysis at the single-cell level by indirect immunofluorescence revealed that mouse cells expressing 9-27 were less permissive for vesicular stomatitis virus than control cells not expressing 9-27. No significant inhibition of influenza virus was observed. When tested in parallel, 9-27 was found to have less powerful antiviral activity toward vesicular stomatitis virus than the interferon-induced MxA protein. Thus, 9-27 joins the family of interferon-induced proteins with intrinsic antiviral activity.