IFN-λ activates the JAK-STAT pathway in R4-GFP and S3-GFP cells.

<p><b>(A)</b> R4-GFP and S3-GFP cells treated with IFN-α (1000 I.U/ml) or IFN-λ (100 ng/ml) for 5, 10 or 30 minutes and Jak phosphorylation was measured by Western blot analysis. <b>(B)</b> R4-GFP cells were treated with a pan-Jak inhibitor (6-Pyridone) for 1 hour prior to IFN-λ (100ng/mL) treatment and after 72 hours the antiviral effect was measured by FACs analysis. <b>(C)</b> STAT1 and STAT2 phosphorylation was determined by 30 minutes treatment of R4-GFP and S3-GFP cells with increasing doses of IFN-α or IFN-λ. <b>(D)</b> S3-GFP and R4-GFP cells were treated with 100ng/mL of IFN-λ and cells were collected at different time points after treatment. Western blotting was performed using antibodies targeting the p38, p-JNK, p-ERK and p-αKT and PKC and beta-αctin.