FIG. 2.

Transfection of CEFs with plasmid DNA induces production of IFN-α/β and represses NDV-GFP replication. CEFs were left untreated (A), were treated with chicken IFN-α/β at 500 U (B) or 1,000 U (C)/ml, or were transfected with the empty expression plasmid pCAGGS (D). IFN treatment was performed in the absence (A to C) or presence (E and F) of neutralizing antibody against chicken IFN. Transfection of cells with empty vector was performed in the absence of anti-IFN antibody (D), or else the antibody was added immediately after the transfection (G). Cells were infected with NDV-GFP at an MOI of 1 at 20 h posttreatment or posttransfection and then examined for green fluorescence at 24 h postinfection.