STIMULATION OF PLASMIN ACTIVITY IN CULTURED HUMAN FIBROBLAST CELLS BYPORPHYROMONAS-ENDODONTALIS

1. Plasmin activity in the conditioned medium of Gin-I cells, a human gingival fibroblast cell line, was stimulated by Porphyromonas endodon talis, a putative pathogen of oral submucous abscesses, in a time- and dose-dependent manner. 2. P. endodontalis stimulated the activity of plasminogen activator in both the conditioned medium and the cell lysa te. The plasminogen activator in Gin-1 cells was approx. 50 Kda by zym ography. 3. The conditioned medium of Gin-1 cells exposed to P. endodo ntalis stimulated the conversion of human serum prekallikrein to kalli krein. 4. These results suggested that P. endodontalis stimulates the plasminogen activator-plasmin system in Gin-1 cells, and that activate d plasmin plays a role in the progress of periodontal tissue inflammat ion.