Porphyromonas gingivalis (Pg), Aggregatibacter actinomycetemcomitans (Aa), Tannerella forsythia (Tf), Prevotella intermedia (Pi), and Fusobacterium nucleatum (Fn) are major periodontal pathogens. Lipopolysaccharides (LPSs) from periodontal bacteria play an important role in periodontal pathogenesis by stimulating host cells to produce inflammatory cytokines. In this study, highly pure LPSs from the five major periodontopathogens were prepared, and their monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-α (TNF-α)-inducing activities were compared in human umbilical vein endothelial cells (HUVECs) and THP-1 macrophagic cells, respectively. In HUVECs, LPSs from Aa and Fn were potent stimulators for MCP-1 induction; however, LPSs from Pg, Pi, and Tf were much weaker MCP-1 inducers. In THP-1 cells, LPSs from Pg, Aa, and Fn were relatively strong inducers of TNF-α, whereas LPSs from Pi and Tf produced little activity. The Toll-like receptor (TLR)2/TLR4 dependency of various LPSs was also determined by measuring NF-κB reporter activity in TLR2- or TLR4-expressing 293 cells. LPSs from Aa, Fn, and Tf stimulated only TLR4; however, LPSs from Pg and Pi stimulated both TLR2 and TLR4. These results suggest that LPSs from major periodontal bacteria differ considerably in their cell-stimulating activity.

Introduction
Materials and Methods
    1. Bacteria and growth conditions
    2. Cell culture
    3. Lipopolysaccharide purification
    4. Measurement of cytokines from culturesupernatants
    5. NF-κB luciferase reporter assay
Results
    1. Comparison of production of MCP-1 and TNF-a byLPSs from periodontal bacteria
    2. Determination of stimulation of TLR2 and TLR4 byLPSs from periodontal bacteria
Discussion
References

• So-Hee Kim(Department of Oral Microbiology, School of Dentistry, Chonnam National University)
• In-Chol Kang(Department of Oral Microbiology, School of Dentistry, Chonnam National University) Correspondence to