Increased ERK activation is required for IL-10 overexpression, and the suppressed p38 pathway is involved in the impaired IL-12p70 production in diffDCs. (A-D) imDCs and diffDCs were pretreated with 10 μmol/mL U0126 (A,B), 10 μmol/mL SB203 580, or 50 μmol/mL SP600 125 for 30 minutes, then stimulated with 500 ng/mL LPS for 24 hours. Equal amounts of DMSO contained in medium were used as negative controls. The levels of IL-10 and IL-12p70 in the supernatants were determined by ELISA. Data were shown as mean plus or minus SD of 3 independent experiments. *P < .05. NS indicates not significant. (E) SP600 125 enhanced p38 activation in imDCs and diffDCs. diffDCs and imDCs were pretreated with 50 μmol/mL SP600 125 for 30 minutes, then stimulated with LPS for 30 minutes. p38 phosphorylation was examined by immunoblotting of cell lysates with anti–phospho-p38 antibody. The membrane was then stripped and total p38 was detected. Similar results were obtained from 3 independent experiments.