The effect of IL-28A on JAK-STAT signaling pathway. GSB1 cells were treated with either IL-28A conditioned medium (A) or recombinant rIL-28A (B) for 30 minutes, followed by protein extraction and Western blot analysis using antibodies as indicated in the figure. Equal amounts (20 ug) of proteins were loaded in each lane and confirmed by detection of actin. STAT1 or STAT3 indicates total STAT protein. p-STAT1 or p-STAT3 indicates tyrosine phosphorylated form (activated STAT protein). The figures are representatives of at least four independent experiments.