To evaluate T cell activation in response to the culture supernatant of KB cells, we examined cell proliferation and interferon gamma (IFN-¦Ã) production, which is closely related to periodontal disease, in Jurkat cells. Culture supernatant of LPS-stimulated KB cells enhanced cell proliferation and IFN-¦Ã production in Jurkat cells. To determine the active component within the culture supernatant, the production of epithelial cell-derived cytokines, interleukin-12 (IL-12), IL-15 and IL-18, in LPS-stimulated KB cells was analysed.
IL-15, but not IL-18, was significantly increased in the culture supernatant of LPS-stimulated KB cells. Moreover, additional anti-IL-15 neutralizing antibody abolished culture supernatant-induced IFN-¦Ã expression in Jurkat cells.
These results suggest that periodontal pathogens induce the production of IL-15 from epithelial cells, and leading the activation of T cells in periodontal lesions.