Itsuo Ueda

Levels of Porphyromonas gingivalis Fimbriae and Inflammatory Cytokines in Gingival Crevicular Fluid from Adult Human Subjects

The Porphyromonas gingivalis fimbriae level was examined in the gingival crevicular fluid (GCF) from adult human subjects using an immunoblot assay with a monoclonal antibody. The cytokines, interleukin‐1α (IL‐1α), IL‐1β, IL‐6 and tumor necrosis factor‐a (TNF‐α) levels in the GCF were quantified by enzyme‐linked immunosorbent assay (ELISA). The reactivity of the GCF samples with the monoclonal antibody against P. gingivalis fimbriae was related to the IL‐1β, IL‐6 and TNF‐α levels. Moreover, the fimbriae content was associated with the gingival index (GI). In contrast, no significant correlation was seen between the fimbriae content and IL‐1α level. These results suggest that there are possible associations between P. gingivalis fimbriae and IL‐1β, IL‐6 and TNF‐α in the gingival crevicular fluid.

Porphyromonas gingivalis Fimbriae Induce Adhesion of Monocytic Cell Line U937 to Endothelial Cells

This study used the human monocytic cell line U937 to examine whether or not Porphyromonas gingivalis fimbriae could induce the adhesion of monocytes to endothelial cells. An in vitro adhesion assay was used to investigate the effects of the fimbriae on U937 cell adhesion to human umbilical vein endothelial cells (HUVEC). The fimbriae enhanced U937 cell adhesion to HUVEC in a dose‐dependent manner. U937 cells adhered better to HUVEC pretreated with the fimbriae for a minimum of 2 hr than to untreated HUVEC. The enhanced adhesion was inhibited by a monoclonal antibody against P. gingivalis 381 fimbriae. Pretreatment of U937 cells with the fimbriae for 24 hr enhanced U937 cell adhesion to HUVEC approximately 4‐fold. This phenomenon was inhibited by an anti‐CD11b antibody, suggesting the involvement of CD11b. These results indicate that P. gingivalis fimbriae can induce monocyte adhesion to the endothelial cell surface. They also suggest that the fimbriae may be involved in the initial event for infiltration of monocytes into the periodontal tissues of individuals with adult periodontitis.