FIG. 3.

Inhibition of cell-to-cell spread of infection and plaque formation by Fab-pp treatment. The cells were infected and incubated for 1 h without antibody and then treated with 500 μg/ml of Fab-pp of clone 10, 11, 24, 36, 60, or 94 for 4 days. The cells were fixed with formalin and stained with methylene blue. Plaques with extensive cytopathology were observed in infected cultures without antibody treatment, while treatment with 500 μg/ml of Fab-pp inhibited the spread of cytopathology. Bars indicate 1 mm.