FIG. 1.

Induction of IFN-α by cell cultures expressing TGEV structural proteins. Vaccinia virus vT7-3-infected RK13 cells were transfected with Lipofectamine containing one or a combination of plasmids, each containing one of the TGEV genes, as indicated. The monolayers were fixed with 0.25% glutaraldehyde at 10 h postinfection and then incubated overnight with PBM cells (10⁷/ml) for IFN induction. TGEV- or mock-infected ST cell monolayers were processed in the same way for comparison. The interferon titer in the maintenance medium was determined by an ELISA test specific for IFN-α.