FIG. 3.

Plating efficiency of mutant PrV on MDBK and NB cells. Titers of wild-type-like PrV-1112, phenotypically gD-complemented PrV gD⁻ (gD⁺ PrV-gD⁻), PrV gD⁻ Pass, and PrV gCD⁻ Pass were determined on MDBK cells (white bars) or NB cells (black bars) by plaque assay and X-Gal staining (A). (B) Plating efficiencies of PrV-1112, PrV gD⁻ Pass, and PrV gCD⁻ Pass on MDBK and NB cells after propagation on a PrV gD-expressing cell line. Average values and standard variations (error bars) of three independent experiments are shown. This corresponds to PFU on MDBK cells and to infected single cells after infection of NB cells with PrV gD⁻ Pass and PrV gCD⁻ Pass. These virus mutants do not form plaques on NB cells irrespective of phenotypic gD complementation.