FIG. 4.

Plaque size of different PrV mutants. RK13, Vero, MDBK, and PSEK cells were infected under plaque assay conditions with gG–β-Gal recombinant PrV-1112, PrV-gE/I⁻, PrV-gM⁻, PrV-gE/I/M⁻, or PrV-gE/I/N⁻. Two days after infection, cells were fixed and stained with X-Gal or crystal violet (for PrV-gE/I⁻). Plaque diameters were measured microscopically. The average diameter of plaques induced by PrV-1112 was counted as 100%, and diameters of plaques induced by the other mutant viruses were calculated accordingly. Bars indicate standard deviation.