歯周病原性細菌Ｐｏｒｐｈｙｒｏｍｏｎａｓ ｇｉｎｇｉｖａｌｉｓシステインプロテアーゼ（ｇｉｎｇｉｐａｉｎｓ） 構造，病原作用および歯周炎予防・治療への有用性

Abstract

Periodontitis results in degradation of periodontal connective tissue and subsequent detachment of the tissue to teeth, and is the main cause of teeth loss. Preventive and therapeutic methods, however, have not been established against the dental disease. Porphyromonas gingivalis is the major causative bacterium of adult periodontitis and the bacterial“trypsin-like”proteinases attract attention as virulence factors. As the “trypsin-like”proteinases, two arginine-specific (gingipain R) (50 kDa and 95 kDa) and one lysine-specific (gingipain K) (105 kDa) cysteine proteinases are purified from the bacterium, the larger proteinases being complexed with adhesin/hemagglutinin domains. Gingipain pathogenic functions were introduced, especially on vascular permeability enhancement induction through prekallikrein activation and subsequent release of bradykinin, fibrinogen degradation and thrombin production through factor X activation. These gingipain functions are closely associated with gingival crevicular fluid production, neutrophil accumulation, bleed-ing tendency, connective tissue and alveolar bone degradation, etc. at periodontitis sites. Thus, gingipains are likely to play a crucial role in the pathogenesis and development of periodontitis, therefore, possible targets in periodontitis control. Immunization using gingipains or their fragments and gingipain specific inhibitor administration will be available for periodontitis prevention and therapy.