Purification and characterization of a fimbrial protein from Porphyromonas salivosa ATCC 49407.

Periodontal disease is a significant problem in companion animals such as dogs and cats. However, there is little information available about fimbriae association of periodontal disease in companion animals. In this study, we have purified and characterized a fimbriae from Porphyromonas salivosa ATCC 49407. The molecular mass of this protein was approximately 60-kDa, as estimated by SDS-PAGE. Immunogold electron microscopy revealed that anti-60-kDa fimbrial serum bound to fimbria on the cell surface of P. salivosa ATCC 49407. However, fimbriae of P. gingivalis and P. gulae were not labeled with the same antibody. Immunoelectron-microscopic studies and immunoblot analysis revealed that antigenicity and molecular weight were distinct from previously reported Porphyromonas fimbrial proteins. The amino acid sequence of the N-terminal 15 residues of the 60-kDa fimbrillin protein revealed only 3 of 15 residues identical to other Porphyromonas species fimbrillin proteins. Thus, the N-terminal amino acid sequence of the 60-kDa fimbrillin protein of P. salivosa clearly differed from previously reported fimbrillin proteins. The level of adherence of the P. salivosa was 1.81%. It was confirmed that P. salivosa can adheres to human cells. These results suggest that the 60-kDa fimbriae of P. salivosa ATCC 49407 is a new type of fimbria and may have an important factor in the adherence host cells. We suggest that the surface structure of P. salivosa may have a role in the colonization of this organism in periodontal pockets in companion animals.

Porphyromonas gulae 41-kDa fimbriae induced osteoclast differentiation and cytokine production.

Porphyromonas gulae is considered to be associated with canine periodontitis. We have previously reported that the P. gulae American Type Culture Collection (ATCC) 51700 comprised 41-kDa fimbriae. The purpose of the present study was to demonstrate the roles of 41-kDa fimbrial protein in periodontal disease. In this study, we examined the involvement of the 41-kDa fimbrial protein in osteoclast differentiation and cytokine production in murine macrophages. Furthermore, alveolar bone resorption induced by P. gulae infection in rats was evaluated. To estimate osteoclast differentiation, bone marrow cells and MC3T3-G2/PA6 cells were cultured with or without the 41-kDa fimbrial protein for 7 days. BALB/c mouse peritoneal macrophages were stimulated with the 41-kDa fimbrial protein, and the levels of interleukin (IL)-1ß and tumor necrosis factor (TNF)-α production were determined by enzyme-linked immunosorbent assay. Osteoclast differentiation was significantly enhanced by treatment with the 41-kDa fimbrial protein in a dose-dependent manner. The total area of pits formed on the dentine slices with osteoclasts incubated with the 41-kDa fimbrial protein was significantly greater than that of the control. The purified 41-kDa fimbrial protein induced IL-1ß and TNF-α production in BALB/c mouse peritoneal macrophages after 6 hr of incubation in a dose-dependent manner. The bone loss level in rats infected with P. gulae was significantly higher than that of the sham-infected rats. These results suggest that P. gulae 41-kDa fimbriae play important roles in the pathogenesis of periodontal disease.