ROLE OF PORPHYROMONAS-GINGIVALIS PROTEASE ACTIVITY IN COLONIZATION OFORAL-SURFACES

Cysteine proteases, including Arg-gingipain of Porphyromonas gingivali s, have been implicated as important virulence factors in periodontal diseases, These enzymes are also involved in the hemagglutinating acti vity of the organisms, In order to determine the role of proteases in the colonization of the gingival margin, we have compared the attachme nt properties of P. gingivalis 381 with those of its Arg-gingipain-def ective mutant, G-102, Interactions with gram-positive bacteria, human oral epithelial cells, extracellular matrix proteins, and type I colla gen were evaluated, In all cases, mutant G-102 was deficient in attach ment relative to the parental strain, The mutant's defects could be ex plained, in part, by the weak autoaggregation displayed by the mutant, which appeared to result from altered fimbrial expression, Both Weste rn blot (immunoblot) and Northern (RNA) blot analyses indicated reduce d expression of the major 43-kDa fimbrillin subunit in the mutant, The se results suggest that Arg-gingipain may play both direct and indirec t roles in the colonization of the gingival margin, In addition, fimbr iae may play a direct role in interacting with some host surfaces.