a, Western blot analysis of Mx2 expression HOS cells transduced with vectors expressing control or Mx2-targeted shRNAs, and treated with IFNα. Numbers below each lane indicate fluorescence intensity associated with the Mx2 band. d, Infectious titer of an HIV-1 GFP reporter virus determined using the shRNA containing HOS cells from a, with or without IFNα treatment. Titers are mean+SD, n=3 technical replicates, representative of three experiments.