Monoclonal antibody against Porphyromonas gingivalis hemagglutinin inhibits hemolytic activity

Porphyromonas gingivalis has been implicated as an important pathogen in the development of adult periodontitis. This bacterium possesses hemagglutinating and hemolytic activities to attach and lyse erythrocytes. Hemolysis by this oral pathogen functions to provide heme-containing molecules for growth in the periodontal pocket. We previously constructed a monoclonal antibody using P. gingivalis vesicles as the immunogen, designated as MAb-Pg-vc, which inhibited vesicle-associated hemagglutinating activity. Furthermore, we cloned the gene encoding 130-kDa hemagglutinin (130-kDa HAG) and identified its functional motif for attachment to erythrocytes. Generally, bacterial cell attachment to erythrocytes is an important initial step for expressing hemolysis activity. In the present study, we examined the effect of MAb-Pg-vc on the hemolytic activity of P. gingivalis cells. The MAb-Pg-vc significantly inhibited the hemolytic activity and, further, this inhibitory activity was reduced by the synthetic peptide of the 130-kDa HAG functional motif.