Fluorescence microscopy.

HT1080 cells were incubated with 1000 IU/mL IFN-α2a for various times indicated. After fixation and permeabilization, PLSCR1 antigen (green fluorescence) was detected using mab 4D2 (see “Materials and methods”). Cell nuclei are counterstained with propidium iodide (red fluorescence). Control IgG refers to IFN-induced cells that were identically treated and stained with IgG1 murine antibody to irrelevant antigen (complement C9) substituting for mab 4D2. Data representative of 2 independent experiments so performed. White bar indicates 50 μ scale.