miR-155 modulates IL-12p70 production in mDCs and enhances IFN-γ production by NK cells. (A) Reduction of IL-12p70 secretion by mDCs after miR-155 silencing. imDCs at day 6 were transfected with anti-miR-155 knockdown probes and scramble probes. Six hours later, cells were treated with the maturation cocktail for another 24 hours. Supernatant was harvested and IL-12p70 was measured by ELISA. The data shown are means with 95% confidence intervals from 3 independent experiments. **P < .01 by 2 sample t test. (B-C) SOCS-1 expression in human monocytes, imDCs, and mDCs by real-time PCR (B) and Western blot (C). (D) SOCS-1 expression in DCs after miR-155 silencing by Western blot. imDCs at day 6 were transfected with 80nM of scramble and miR-155 KO probes for the indicated time. Cells were analyzed for SOCS-1 expression by Western blot. (E) SOCS-1 expression in imDCs after miR-155 overexpression. imDCs at day 5 were transfected with 40nM of miR-155 precursors for 24 hours and then analyzed by Western blot. (F) Overexpression of miR-155 in DCs increased IL-12p70 secretion. imDCs at day 6 were transfected with 40nM of miR-155 or miR-198 precursors or negative controls. Six hours later, cells were treated with the maturation cocktail for another 8, 16, and 24 hours. Supernatants were harvested, and IL-12p70 was measured by ELISA. The data are mean ± SEM from 3 independent experiments. A linear mixed model with random subject effect was used to evaluate miRNA groups and time effects. There was a significant difference between the miR-155 and other groups (P < .01). (G) imDCs at day 6 were transfected with 40nM of miR-155 precursors or negative controls. Six hours later, cells were treated with the maturation cocktail for another 12 hours. After washing, DCs were cocultured with autologous NK cells at the ratio of 1:2 for 24 hours. Supernatants were harvested, and IFN-γ was measured by ELISA. The data are from 2 independent experiments with 2 different donors. Values represent the mean ± SD. **P < .01 by Student t test.