c-Abl is required for IL-2 production in T cells. (A) Jurkat T cells were transfected with vector or shAbl-3 together with a luciferase reporter gene under the control of the IL-2 promoter. After 48 hours, cells were stimulated with the indicated antibodies (left) or with Raji B cells pulsed with SEE (right) for 6 hours, and IL-2 promoter activity was assayed. (B) T cells purified from lymph nodes and spleens of abl^flox/floxCD4-Cre⁺ and littermate control mice (abl^flox/floxCD4-Cre⁻) were lysed and blotted with anti–c-Abl. GAPDH expression from the same blot is shown as a loading control. (C) T cells prepared as in panel B were incubated with APCs plus the indicated doses of 2C11 or SEB for 24 hours. IL-2 levels in the supernatant were measured by ELISA. All data represent the average plus or minus the standard deviation of quadruplicate samples from 1 experiment (representative of 3 independent experiments). **P < .01.