Characterization of Tannerella forsythensis lipopolysaccharide

Tannerella forsythensis is a gram negative anaerobic bacterium that has been closely associated with severe periodontitis. Its virulence factors however, such as lipopolysaccharide (Tf LPS) have not been characterized. Objectives: Isolate and characterize the LPS of Tannerella forsythensis strain 9610 and examine its ability to stimulate inflammatory mediator production by cells of the innate immune system. Methods: Tf LPS was isolated by a modified cold magnesium/ ethanol precipitation procedure performed at pH 7.5. It was characterized by gas chromatography, mass spectrometry and standard chemical methods. Cultured human endothelial cells and monocytes were stimulated with Tf LPS and assayed by ELISA for E-selectin and IL-8 respectively. Results: T. forsythensis 9610 produces a smooth form LPS containing the sugars glucose and mannose. It has a monophosphoryl, primarily pentaacylated lipid A containing 16 carbon unbranched and 17 carbon branched 3- hydroxy-fatty acids as well as branched 15 and unbranched 16 carbon fatty acids. Tf LPS is a more a more potent stimulator of IL-8 from human monocytes than P. gingivalis LPS but less potent than LPS from E. coli. Tf LPS was a very poor stimulator of E-selectin expression on endothelial cells and similarly to P. gingivalis LPS, was a potent antagonist of E. coli stimulated E-selectin. Conclusion: The lipopolysaccharide from T. forsythensis has the ability to both stimulate inflammatory mediator production from host cells and to antagonize the effects of other LPS on mediator production. Supported by NIH/NIDCR DE12768-01 and DE07023