Cytokine Responses toTreponema pectinovorumandTreponema denticolain Human Gingival Fibroblasts

Abstract

Human gingival fibroblasts were challenged with Treponema pectinovorum and Treponema denticola to test three specific hypotheses: (i) these treponemes induce different cytokine profiles from the fibroblasts, (ii) differences in cytokine profiles are observed after challenge with live versus killed treponemes, and (iii) differences in cytokine profiles are noted from different gingival fibroblast cell lines when challenged with these treponemes. Three normal gingival fibroblast cell cultures were challenged with T. pectinovorum and T. denticola strains, and the supernatants were analyzed for cytokine production (i.e., interleukin-1␣ [IL-1␣], IL-1␤, IL-6, IL-8, IL-10, gamma interferon, macrophage chemotactic protein 1 [MCP-1], platelet-derived growth factor, tumor necrosis factor alpha, and granulocyte-macrophage colony-stimulating factor). Unstimulated fibroblast cell lines produced IL-6, IL-8, and MCP-1. T. pectinovorum routinely elicited the greatest production of these cytokines from the fibroblast cell lines, increasing 10-to 50-fold over basal production. While T. denticola also induced IL-6 and IL-8 production, these levels were generally lower than those elicited by challenge with T. pectinovorum. MCP-1 levels were significantly lower after T. denticola challenge, and the kinetics suggested that this microorganism actually inhibited basal production by the fibroblasts. No basal or stimulated production of the other cytokines was observed. Significant differences were noted in the responsiveness of the various cell lines with respect to the two species of treponemes and the individual cytokines produced. Finally, dead T. pectinovorum generally induced a twofold-greater level of IL-6 and IL-8 than the live bacteria. These results supported the idea that different species of oral treponemes can elicit proinflammatory cytokine production by gingival cells and that this stimulation did not require live microorganisms. Importantly, a unique difference was noted in the ability of T. pectinovorum to induce a robust MCP-1 production, while T. denticola appeared to inhibit this activity of the fibroblasts. While the general cytokine profiles of the fibroblast cell cultures were similar, significant differences were noted in the quantity of individual cytokines produced, which could relate to individual patient variation in local inflammatory responses in the periodontium.

Immune Response and Alveolar Bone Resorption in a Mouse Model ofTreponema denticolaInfection

“…Ruby et al (23) recently reported that T. denticola can induce the production of IL-10 and a number of proinflammatory cytokines, such as IL-1␤, IL-6, IL-12 p70, and tumor necrosis factor, by macrophages. Nixon et al (21) demonstrated that T. denticola induced production of IL-6 and IL-8, but not MCP-1, by human gingival fibroblasts, while Treponema pectinovorum induced all three cytokines. Interestingly, our results showed that splenocytes from mice infected with T. denticola no longer produced IL-10 and had markedly decreased IFN-␥ production upon in vitro stimulation with T. denticola.…”

Upregulation of Intercellular Adhesion Molecule 1 and Proinflammatory Cytokines by the Major Surface Proteins of Treponema maltophilum and Treponema lecithinolyticum , the Phylogenetic Group IV Oral Spirochetes Associated with Periodontitis and Endodontic Infections

“…The surface molecules that showed enhanced IL-8 secretion were P. gingivalis gingipain-R (40), a glycoprotein fraction in the cell surface from P. intermedia (48), and a capsular polysaccharide from Actinobacillus actinomycetemcomitans (39). Several oral treponemes have been reported to stimulate proinflammatory cytokines in various cell types, such as gingival fibroblasts and gingival epithelial cells (2,25,37,43). However, with the exception of their LPS or LPS-like materials, none of them has been analyzed at the molecular level.…”

Detection and Quantification of Oral Treponemes in Subgingival Plaque by Real-Time PCR

“…Oral treponemes have been observed to adhere to and invade connective tissues, as well as gingival epithelial cells (1,12,20,27), and also induce cytokine production from human gingival fibroblasts (18). Therefore, it is suggested that they play an important role in causing periodontal diseases.…”