FIG. 1.

Growth kinetics of PRV Be and PRV EP0-1 in PELF cells untreated and pretreated with porcine IFN-α. Cells were either untreated or treated with IFN-α for 24 h prior to infection with either PRV Be or PRV EP0-1 at a multiplicity of infection of 10. Extracellular and intracellular virus was collected at the indicated times postinfection, and the titers were determined by plaque assay (n = 2).