PORPHYROMONAS-GINGIVALIS PROTEINASES AS VIRULENCE FACTORS IN THE DEVELOPMENT OF PERIODONTITIS

Porphyromonas gingivalis contains exceedingly high concentrations of c ysteine proteinases with trypsin-like activity which have been implica ted as virulence factors in adult-onset periodontitis. These enzymes, referred to as gingipains, cleave protein and peptide substrates after arginine (gingipain R) and lysine residues (gingipain K), and it has been found that neither is easily inhibited by host proteinase inhibit ors. Examination of the properties of each proteinase clearly indicate s a role(s) for both in the dysregulation of a number of normally tigh tly controlled pathways. The effects of such uncontrolled proteolysis are the development of edema (kallikrein/kinin pathway activation by g ingipain R), neutrophil infiltration (complement pathway activation by gingipain R), and bleeding (degradation of fibrinogen by gingipain It ). Since three of the major hallmarks of periodontitis involve increas ed crevicular flow, neutrophil accumulation at infected sites and blee ding on probing: it seems likely that both P. gingivalis-derived prote inases are important virulence factors in the development of periodont al disease.