INTERLEUKIN-1, INTERLEUKIN-6 AND TRANSFORMING GROWTH-FACTOR-BETA PRODUCTION BY HUMAN GINGIVAL MONONUCLEAR-CELLS FOLLOWING STIMULATION WITH PORPHYROMONAS-GINGIVALIS AND FUSOBACTERIUM-NUCLEATUM

Gingival mononuclear cell production of interleukin 1 (IL-1), interleu kin 6 (IL-6) and transforming growth factor-beta (TGF-beta) after stim ulation with the putative periodontopathic bacteria, Porphyromonas gin givalis and Fusobacterium nucleatum was investigated. Using an ELISA m ethod, gingival mononuclear cells extracted from 18 adult periodontiti s subjects were found to be producing IL-1. However, IL-1 activity cou ld only be detected in 5 out of these 18 cases when tested using a thy mocyte proliferation bio-assay, suggesting the presence of IL-1 inhibi tors. Depletion of monocytes from peripheral blood cultures resulted i n a significant decrease in IL-1 activity following P gingivalis stimu lation while there was no effect in the level of IL-1 activity followi ng stimulation with F. nucleatum. This suggests that P gingivalis and F nucleatum stimulate different cell types to produce IL-1. Like IL-1, IL-6 production by gingival mononuclear cells was significantly great er than that produced by the control peripheral blood mononuclear cell s. Following P gingivalis and F nucleatum stimulation, higher levels o f IL-6 could be detected; however, both organisms stimulated similar l evels. Intracytoplasmic immunofluorescence staining demonstrated a low er percent TGF-beta+ cells in bacterial stimulated peripheral blood mo nonuclear cell cultures compared with cells in medium alone. In the gi ngival mononuclear cell cultures, the percentage TGF-beta+ cells peake d at day 1 in F nucleatum-stimulated, whereas in P gingivalis-stimulat ed cultures the peak TGF-beta+ cells occurred at day 3, again suggesti ng stimulation of different cell subsets. These results illustrate tha t different periodontopathic bacteria may stimulate different cell typ es to produce cytokines which may have synergistic or antagonistic eff ects.