Expression of the mitotic regulatory proteins, cyclin B and cdc2, in uninfected and HHV-7–infected cells evaluated by immunoblotting analysis of whole cell lysates (A) and by flow cytometric analysis (B). (A) Equivalent amounts of protein lysates obtained from HHV-7–infected and uninfected SupT1 cells were analyzed by Western blot with an anti-cyclin B and with an anti-cdc2 MoAb. Equal loading of protein in each lane was confirmed by staining with the antibody to tubulin. The relative intensities of the bands were densitometrically quantified and expressed in arbitrary units (a.u.). (B) Intracellular expression of cyclin B and cdc2 proteins was analyzed in uninfected and HHV-7–infected cells by indirect immunofluorescence staining shown by flow cytometry. A representative analysis, performed at 12 days p.i., is shown. A shift in the number of positively staining fluorescent cells along the X axis (shaded histograms) shows the increased level of cyclin B and cdc2 expression in HHV-7–infected cultures. The control (open) histograms represent the background intracellular fluorescence obtained from the staining of the same cultures with a isotype control MoAb before FITC-conjugated secondary Ab. Y axis, relative cell number. Data shown are from a single experiment representative of four independent experiments with similar results.