FIG. 9.

Response of HEK293T cells expressing NOD1 to muropeptides 6 to 9. Induction of NF-κB activation was determined in triplicate cultures of HEK293T cells transiently transfected with the pcDNA-NOD1 expression vector in the presence of pELAM-Luc, pRL-TK, and pcDNA3 plasmids. Forty-four hours posttransfection, cells were treated with the synthetic compounds 6 to 9 (5 μM each) or were left untreated (control). Forty-eight hours posttransfection, NF-κB activation, as firefly luciferase activity relative to Renilla luciferase activity, was determined. In the transfection experiment shown, human TNF-α (10 ng/ml) induced 10.8-fold ± 0.9-fold activation of NF-κB. Asterisks indicate significant differences from untreated (control) cells (P < 0.05).