Inhibition of ATF2 gene expression using specific siRNA in human CD4⁺ decreases the transactivation activity of steroids. Introduction of ATF2 siRNA into CD4⁺ T cells resulted in specific inhibition of ATF2 expression as shown by (A) real-time PCR and (B) immunostaining (original magnification ×630; blue, DAPI, nuclear staining; red, cy3, ATF2; see “Materials and methods, GCRα nuclear translocation” for more detailed image acquisition information). The pictures are representatives of 4 independent experiments. Silencing of ATF2 resulted in a significant decrease of DEX-induced (C) MKP-1 and (D) IL-10 production by human CD4⁺ T cells (n = 4) compared with a nonspecific siRNA control group.