Histatin 5 inhibits inflammatory cytokine induction from human gingival fibroblasts by Porphyromonas gingivalis

Porphyromonas gingivalis is a gram-negative rod associated with the progres sion of human periodontal disease. It has been demonstrated that outer-memb rane proteins as well as lipopolysaccharides from P. gingivalis ATCC 53977 can induce interleukin 6 (IL-6) and IL-8 from the cells of the periodontium in vitro. But, they cannot induce IL-l and tumor necrosis factor-ct from t he cells. In the present study. we studied the effects of salivary protein on cytokine induction from human gingival fibroblasts by P. gingivalis oute r-membrane protein. Histatin 5 suppressed the IL-6 and IL-8 induction by P. gingivalis outer-membrane protein. This activity was more effective when o uter-membrane protein was incubated with histatin 5 before addition to the cell culture. The present study indicates that histatin 5 restrains inducti on of inflammatory cytokines by periodontal pathogens and that histatin is one of the salivary proteins responsible for this activity.