Fig 4.

Induction of IFN and interferon-stimulated genes in vivo. BALB/c mice were treated intramuscularly (A) or intranasally (B) with 50 μl of PBS containing 4 μg of pIC (orange bars), SeV RNA (green bars), IVT DI RNA (blue bars), or PBS alone. Six hours later the calf muscles (A) or the lungs (B) were extracted and total RNA isolated. The levels of mRNA for IFN-β, Mx, and IP-10 then were measured by qRT-PCR. Data represent the mRNA fold induction for individual genes above the level for the PBS-treated mice. (C) RNase treatment of SeV RNA and the IVT DI RNA. The RNAs were digested (+) or mock treated (−) and injected i.m. into the calf muscle of mice to monitor their stimulatory activity. The fold induction of the mock-treated RNA was set to 100%. (D) Induction of IFN and ISGs in RIG-I^−/− versus RIG-I^+/+ mice. Mice were injected with pIC (4 μg), IVT DI (4 μg), and PBS via the i.m. route. Six hours later, the mRNA from the muscle was extracted and analyzed by qRT-PCR. Results represent the fold induction above the level of the PBS-treated samples. Error bars represent standard deviations from three replicates. *, P < 0.5; **, P < 0.01.