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

Porphyromonas gingivalis is a gram‐negative rod associated with the progression of human periodontal disease. It has been demonstrated that outer‐membrane 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‐1 and tumor necrosis factor‐α from the cells. In the present study, we studied the effects of salivary protein on cytokine induction from human gingival fibroblasts by P. gingivalis outer‐membrane protein. Histatin 5 suppressed the IL‐6 and IL‐8 induction by P. gingivalis outer‐membrane protein. This activity was more effective when outer‐membrane protein was incubated with histatin 5 before addition to the cell culture. The present study indicates that histatin 5 restrains induction of inflammatory cytokines by periodontal pathogens and that histatin is one of the salivary proteins responsible for this activity.