Morphological characterization of enlarged (diameter, >20 μm) cells from HHV-7–infected SupT1 cultures. (A) Light micrographs showing cells with a progressively increasing size (a through c) having prominent and lobulated nucleus. (B) Light micrographs of serial semithin (1 μm) plastic sections of the same cells. Note that the multiple nuclear sections evident in panel c belong to the same irregular nucleus shown in panels a and b. (C) Confocal microscope images of the nucleus of a giant HHV-7–infected cell after staining of the DNA with propidium iodide. (a through c) Confocal sections were taken 0.5 μm apart. Whereas two nuclear lobes were clearly separated in panel a, they appeared connected by a nuclear bridge in successive sections (panels b and c). In (B) and (C), the arrow shows the same point in different sections. Original magnification in (A) and (B) × 400; in (C) × 1,000.