Silencing of p38 expression in human blood CD14⁺ cells. (A) Cells were cultured with control or p38 siRNA. After 2 days, total extracts were prepared and analyzed for p38 and β-actin by Western blotting. One of 3 separate experiments is shown. (B,C) IL-25 fails to inhibit the cytokine expression induced by LPS and PGN in p38-deficient cells. Cells were treated with control or p38 siRNA, then stimulated with IL-25 for 30 minutes followed by LPS/PGN for 6 hours. Data indicate mean (± SD) of 5 separate experiments in which cells purified from 5 healthy donors were used.