OmpA-sal induces TLR4 expression, ERK activation, and p38 MAPK activation, but not JNK activation. Total RNA was extracted, and quantitative real-time PCR was performed using sequence-specific primers for TLR2 and TLR4 (A).. Cell lysates were prepared and blotted with anti-phopho-p38, anti-p38, anti-phopho-ERK1/2, anti-ERK1/2, anti-phopho-JNK1/2, and anti-JNK1 antibody. A signal was detected with biotinylated goat-anti mouse IgG and visualized using enhanced chemiluminescence (B). DCs, TLR2-/-DCs, and TLR4-/-DCs were cultured for 24 h in the presence of 200 ng/ml of LPS or 400 ng/ml of OmpA-sal and the production levels of IL-12 analyzed by ELISA (C). BM-DCs and TLR4-/-DCs were cultured for 24 h in the presence of 400 ng/ml of OmpA-sal and surface markers analyzed by flow cytometry (D). The data are the means and standard deviation of three experiments. **, P < 0.01 for a compare with untreated DCs.