FIG. 3.

Wild-type IV and JW strains replicate less efficiently than does Edmonston in the nondividing population of IFN-treated cells. Human PBL were labeled with CFSE and incubated overnight with 2,000 U of IFN-α/β per ml. Cells were then infected with Edmonston, IV, or JW viruses. Cell proliferation and surface expression of hemagglutinin were quantitated by dual-color flow cytometry. Proliferation in the absence of IFN (A) or in the presence of IFN (B) is plotted against surface hemagglutinin expression. This figure is representative of several experiments.