IDENTIFICATION AND POSSIBLE FUNCTION OF CATHEPSIN-G IN GINGIVAL CREVICULAR FLUID FROM CHRONIC ADULT PERIODONTITIS PATIENTS AND FROM EXPERIMENTAL GINGIVITIS SUBJECTS

The levels of cathepsin G in gingival crevicular fluid (GCF) from chro nic adult periodontitis patients and experimental gingivitis subjects were determined both by activity measurement using N-benzoyl-(DL)-phen ylalanine-2-naphthyl ester as a substrate and by enzyme immunoassay us ing anti-human cathepsin G IgG. The activity level of cathepsin G in G CF of both periodontitis and experimental gingivitis has no significan t correlation with all measured clinical parameters. Western immunoblo tting using antibodies specific for cathepsin G or al-proteinase inhib itor revealed that the difficulty in demonstrating the association of its activity with the severity of these diseases was due largely to fo rmation of the enzyme-inhibitor complexes. By contrast, statistically significant positive correlation was found between cathepsin G content in GCF of periodontitis, which was determined by enzyme immunoassay, and such clinical parameters as the GCF volume, the gingival index and probing depth. The increased cathepsin G content with increasing seve rity of periodontal inflammation was markedly diminished by the initia l treatment. Although no significant activity was detectable in GCF of experimental gingivitis, a rapid increase of the immunoreactive cathe psin G was found in GCF at 3-5 d after refraining from oral hygiene me asures, which rapidly decreased by 10 d. The progressively increased c athepsin G between 10th and 21st d rapidly decreased by cleaning of th e teeth. The results indicate that cathepsin G is involved in the host 's defensive mechanism against the invasion of etiologic microbes and/ or the development of either periodontitis or gingivitis.