MiR-146a impairs IL-2 production and AP-1 activity. (A) pRRL-ct and pRRL-146a Jurkat cells were stimulated with anti-CD3/CD28 Abs for 4 and 24 hours and IL-2 levels were determined by ELISA assay. Each bar is the mean of 3 independent experiments. (B) Jurkat cells were cotransfected with the (AP-1)-luc reporter plasmid together with pGL3-tk-luc used for normalization of transfection. Cells were stimulated with anti-CD3/CD28 Abs for 24 hours and the relative promoter activity was measured by renilla/firefly Dual-Luciferase assay. Relative promoter activity in stimulated cells is compared with that in nonstimulated cells, which is set to 1. Each bar is the mean of 3 independent experiments (P < .05).