FIG. 3.

Production of infectious CCHFV from SKI-1/S1P-deficient cells can be rescued by plasmid-expressed SKI-1/S1P. (A) SKI-1/S1P-deficient cells (SRD12B cells) were transiently transfected with control empty vector (top, −SKI-1/S1P) or with SKI-1/S1P-containing vector (bottom, +SKI-1/S1P) by use of a Nucleofector II electroporator, the H-014 program, and cell line Nucleofector solution T (Amaxa, Gaithersburg, MD). These transfected cells were infected 24 hpi and processed at the indicated times postinfection as described in the legend for Fig. 2. No obvious cytopathic effect was observed in the presence or absence of SKI-1/S1P (data not shown). (B) Infections were set up as described above. Infected cell supernatants were collected, clarified, and frozen in liquid nitrogen at the indicated times for subsequent titration by plaque assay on SW13 cell monolayers (22). Red bars indicate viral titers from −SKI-1/S1P-transfected and blue bars from +SKI-1/S1P-transfected cell supernatants.