FIG. 9.

Restored inducibility of CD28 responsive element by ectopic expression of v-Jun. Jurkat (Jk) and C-expressing (JHC.d) cells were cotransfected with a luciferase reporter plasmid driven by four composite CD28REs and either an empty vector control (−) or a plasmid encoding v-Jun. At 40 h posttransfection, the cells were stimulated with TPA and an Ab recognizing CD28 (α-CD28) for 6 h, and luciferase activities was determined. The data presented are means ± SEM of four independent experiments, which were normalized to stimulated Jurkat cells.