(A) STAT DNA binding to the IL-2R GAS-c/GAS-n in response to cytokine stimulation. T cells were stimulated with IFN-, IL-2, IL-12, or IL-15 as indicated; nuclear extracts were prepared from the cells; and the STAT DNA binding was analyzed by EMSA. (B) STAT DNA binding to the IL-2R GAS-c/GAS-n in response to IFN- and IL-2. T cells were stimulated with IFN- or IL-2 for 30 minutes, after which nuclear extracts were prepared. Nuclear extracts were incubated for 1 hour on ice with STAT antibodies indicated, followed by binding to ³²P-labeled IL-2RGAS-c/GAS-n probe. (C) STAT DNA binding to the IL-2RGAS-c/GAS-n in response to IL-12 and IL-15. T cells were stimulated with IL-2 or IL-15 for 30 minutes, and nuclear extracts were prepared and incubated for 1 hour on ice with different anti-STAT antibodies followed by binding to ³²P-labeled IL-2RGAS-c/GAS-n probe. The results are representative of three separate experiments.