MxB antiviral activities. (A) Western blot of HOS cells expressing MxB-HA. β-actin was monitored to control for sample loading. (B) Western blot of untransduced or MxB-HA expressing HOS cell lysates extracted after treatment for 24 h with 1,000 U/ml of interferon α (IFN) as indicated. (C) Immunofluorescence microscopy of HOS cells stably expressing MxB-HA or mock-transduced cells. Blue-tinted ovals demarcate cell nuclei due to Hoescht 33342 staining of DNA. White horizontal bar, 10 μm. (D) Infection of MxB-HA expressing cells with various retroviral vectors plotted as percent infection of mock-transduced cells. Results are a summary of 6 independent experiments with error bars denoting 95% confidence intervals.