COMPARISON OF HOST TISSUE AND BACTERIAL DIPEPTIDYL PEPTIDASES IN HUMAN GINGIVAL CREVICULAR FLUID BY ANALYTICAL ISOELECTRIC-FOCUSING

Earlier work has shown that gingival crevicular fluid (GCF) contains d ipeptidyl peptidase (DPP) activities that resemble those in host tissu e. Here, further comparisons were made with enzymes from suspected per iodontal pathogens. Gingival tissue and GCF were collected from patien ts with chronic periodontitis. DPP II and DPP IV fractions with acid a nd alkaline pH optima, respectively, were separated from crude tissue extracts by gel-filtration chromatography. Bacterial cell sonicates we re prepared from broth cultures of reference strains. There was modera te to strong DPP activity with Capnocytophaga spp., Porphyromonas ging ivalis and Prevotella spp., very weak activity with Treponema denticol a and no detectable activity with Actinobacillus actinomycetemcomitans or Fusobacterium nucleatum. Banding patterns in GCF, tissue and bacte rial samples were compared on substrate-impregnated overlay membranes applied to isoelectric focusing gels. In gels washed with acid buffer, GCF had bands corresponding to tissue DPP II. Use of an alkaline wash ing buffer showed GCF activity which closely matched tissue DPP IV tha t had been pretreated with neuraminidase, an enzyme found by others in the gingival crevice. P. gingivalis gave multiple bands and several o f these had counterparts in GCF. The apparent presence in GCF of the D PP from P. gingivalis is consistent with the association of this organ ism with destructive periodontitis.