Gingipain‐dependent augmentation by Porphyromonas gingivalis of phagocytosis of Tannerella forsythia

This study investigated the role of gingipains in the modulation by P. gingivalis of phagocytosis of Tannerella forsythia by macrophages. Phagocytosis of T. forsythia was significantly enhanced by coinfection with P. gingivalis in a multiplicity of infection‐ and gingipain‐dependent manner. Mutation of either Kgp or Rgp in the coinfecting P. gingivalis resulted in attenuated enhancement of T. forsythia phagocytosis. Inhibition of coaggregation between the two bacterial species reduced phagocytosis of T. forsythia in mixed infection, and this coaggrgation was dependent on gingipains. Inhibition of gingipain protease activities in coinfecting P. gingivalis abated the coaggregation and the enhancement of T. forsythia phagocytosis. However, direct effect of protease activities of gingipains on T. forsythia seemed to be minimal. Although most of the phagocytosed T. forsythia were cleared in infected macrophages, more T. forsythia remained in cells coinfected with gingipain‐expressing P. gingivalis than in cells coinfected with the gingipain‐null mutant or infected only with T. forsythia at 24 and 48 hours post‐infection. Collectively, these results suggest that P. gingivalis, mainly via its gingipains, alters the clearance of T. forsythia, and provide some insights into the role of P. gingivalis as a keystone pathogen. This article is protected by copyright. All rights reserved.
Source: Oral Microbiology and Immunology - Category: Microbiology Authors: Tags: Original Article Source Type: research