EMSA analysis of IFN-induced DNA binding complexes. Monocytes were treated with 10 ng/mL of IL-10 for 90 minutes, followed by treatment with the indicated doses of IFN for 30 minutes. Nuclear extracts were prepared, and EMSA were performed. (A) EMSA using the ISRE probe, which represents binding of the ISGF3 complex. (B) Summaries of the Phospho-Imager data from several experiments, such as those presented in (A), were quantitated using the Phospho-Imager. The value given is the mean ± standard deviation. (C) EMSA using the GRR probe, which predominantly measures binding of STAT1 dimers.