FIG 1.

TLR activation by Porphyromonas gulae whole cells. HEK-Blue cells transfected with the pattern recognition receptor NOD2 (a), TLR2 (b), or TLR4 (c) (2 × 10⁴ cells/well) were incubated with P. gulae whole cells at various MOI for 2 h and then washed with DMEM containing antibiotics. After 24 h, the amount of alkaline phosphatase secreted into the medium was measured as a direct correlation of NF-κB phosphorylation. The assay was repeated twice on each of three biological replicates (n = 6). HEK-Blue cells expressing NOD1, TLR5, TLR7, TLR8, or TLR9 were also tested but did not respond to whole P. gulae cells.