Cytokine degradation by biofilms of Porphyromonas gingivalis

The aim of this study was to determine whether biofilms of Porphyromonas gingivalis could proteolytically degrade the cytokines interleukin (IL)-1 beta, IL-6, or IL-1 receptor antagonist (IL-1ra). Biofilms were grown on membrane filters an the surface of Wilkins-Chalgren blood agar: The biofilms were removed from the plates, and solutions containing 2.5 mu g/ml of each cytokine were added, Following incubation for up to 4.0 h, supernatants from the biofilms were subjected to SDS-PAGE. The separated proteins were transferred by Western blotting to PVDF membranes and probed with peroxidase-conjugated antibodies recognizing both the intact cytokines and their degradation products. After 2 h, no intact IL-1 beta, 1L-6, or IL-1ra were detectable, Cytokine proteolysis also occurred in the presence of horse serum, These results demonstrate that biofilm-grown It gingivalis can degrade both pro-and anti-inflammatory cytokines and so may be able to perturb cytokine networks in vivo by eliminating cytokines from the local environment.