Production of inflammatory cytokines by human gingival fibroblasts stimulated by cell-surface preparations of Porphyromonas gingivalis

Porphyromonas gingivalis is a gram-negative rod associated with the progres sion of human periodontal disease. Inflammatory cytokines are believed to b e the major pathological mediators in periodontal diseases. We therefore in vestigated the productions of interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor-alpha (TNF-alpha) in human gingival fibroblasts treated with lipopolysaccharide, polysacchari de and outer-membrane proteins from P. gingivalis ATCC 53977. Outer-membran e protein from P. gingivalis enhanced the production of IL-6 and IL-8 from the cells of periodontium in vitro as well as lipopolysaccharide did. The I L-8 production activity of polysaccharide from P. gingivalis was higher tha n that of other cell-surface components. The levels of IL-6 and IL-8 releas ed from the P. gingivalis lipopolysaccharide-treated human gingival fibrobl asts were lower than those of the same cells treated with lipopolysaccharid es from Actinobacillus actinomycetemcomitans or Escherichia call. Rabbit an tisera against either outer-membrane protein or lipopolysaccharide inhibite d the IL-6 and IL-8 production derived from human gingival fibroblasts stim ulated sonicated supernatants from P. gingivalis. The present study suggest s that, in addition to lipopolysaccharide, outer-membrane protein and polys accharide of P. gingivalis are also pathological mediators in periodontal d iseases.