Human monocytes and gingival fibroblasts release tumor necrosis factor-α, interleukin-1α and interleukin-6 in response to particulate and soluble fractions ofPrevotella melaninogenica andFusobacterium nucleatum

Summary

In this study we provide evidence that structural and soluble components of periodontopathogenic bacteria, such asPrevotella melaninogenica andFusobacterium nucleatum, induce the release of cytokines in vitro known to cause in vivo necrotic inflammatory phenomena and bone resorption (tumor necrosis factor-α, interleukin-1α and interleukin-6). Human monocytes and gingival fibroblasts were cultivated in vitro in the presence of both particulate and soluble bacterial fractions. A dose-dependent production of tumor necrosis factor-α by monocytes and gingival fibroblasts was observed in the presence of fractions ofP. melaninogenica andF. nucleatum. Interleukin-1α was produced in approximately the same quantities in the presence of soluble fractions of eitherP. melaninogenica orF. nucleatum, but in greater quantities in response to particulate fractions ofP. melaninogenica. Monocytes release larger amounts of interleukin-1α (about 3000 pg/ml) than gingival fibroblasts (about 1500 pg/ml). Interleukin-6 was released in greater quantities by monocytes in the presence of the pellet fraction ofP. melaninogenica (about 5.5 ng/ml), but gingival fibroblasts released larger amounts of interleukin-6, especially in the presence of particulate and soluble components ofF. nucleatum (about 12 ng/ml). The ability to induce the release of these cytokines notably increases the pathogenic potential of the bacteria involved in the damage of periodontal tissue.