FIG. 1.

SARS-CoV encodes an IFN antagonist. (A) MA104 cells were infected with SARS and SeV or mock infected for 12 h. Extracted RNA was analyzed by RT-PCR for the induction of IFN-β mRNA. RT-PCR-amplified GAPDH transcripts are shown as a loading control. (B) Media from icSARS-, Urbani virus-, and SeV-infected MA104 cells were analyzed for secreted type I IFN across a time course of infection. An IFN bioassay (as described in Materials and Methods) was used to analyze the amount of type I IFN secreted from infected cells. The dotted line is the minimal level of detection for the assay.