Splenocytes were isolated from mPGES-1 WT and null mice at day 10 post immunization with DNP-KLH in CFA. (A) Protein expression of COX-1, COX-2, mPGES-1, hPGDS and HPRT in splenocytes cultured with or without DNP-KLH (10 μg/ml) for day 4 was determined by Western blotting. Results are representative examples from 4 mice. Levels of protein expression were normalized against HPRT; data are shown as the fold induction relative to WT DNP-KLH (assigned the value “1”) and are the mean ± SEM from 4 mice. Single, double and triple characters indicate significance at P<0.05, P<0.01 and P<0.001, respectively. *, WT control versus WT DNP-KLH; #, WT DNP-KLH versus null DNP-KLH; $, null control versus null DNP-KLH. (B) Cells were cultured with or without DNP-KLH (10 μg/ml) for indicated days. The levels of PGE2 and PGD2 in culture medium were measured by ELISA. Data are expressed as mean ± SEM (n=7). Single, double and triple characters indicate significance at P<0.05, P<0.01 and P<0.001, respectively. *, WT control versus WT DNP-KLH; #, WT DNP-KLH versus null DNP-KLH; $, null control versus null DNP-KLH.