CD115 is a target of miR-155. (A) Multiple species sequence alignment of the CD115 3′-UTR, including the predicted miR155 target site sequence (in bold). Mutation of the miR155 target site sequence is shown below. (B) Luciferase reporter assays to confirm targeting of CD115 3′-UTR by miR-155. The data are means with 95% confidence intervals from 2 independent experiments. **P < .01 by 2 sample t test. (C) Forced overexpression of miR-155 down-regulated CD115 expression in imDCs. imDCs at day 4 were transfected with miR-155 precursors (black solid line) or negative controls (dotted gray line) for 24 hours. Cells were then stained with an isotype control antibody (tinted) or anti-CD115. (D) Higher levels of CD115 expression in DCs from miR-155^−/− (KO) mice after LPS stimulation. BM-derived imDCs from WT and KO mice were purified with anti-CD11c microbeads and stimulated with LPS (10 ng/mL) for 24 hours. Cells were then analyzed for CD115 expression by flow cytometric analysis.