title: Synergistic virulence of Porphyromonas gingivalis and Treponema denticola in a murine periodontitis model.
abstract: Chronic periodontitis is characterized by the destruction of the tissues supporting the teeth and has been associated with the presence of a subgingival polymicrobial biofilm containing Porphyromonas gingivalis and Treponema denticola. We have investigated the potential synergistic virulence of P. gingivalis and T. denticola using a murine experimental model of periodontitis. An inoculation regime of four intra-oral doses of 1 × 10(10) P. gingivalis cells induced significant periodontal bone loss compared with loss in sham-inoculated mice, whereas doses of 1 × 10(9) cells or lower did not induce bone loss. Inoculation with T. denticola with up to eight doses of 1 × 10(10) cells failed to induce bone loss in this model. However, four doses of a co-inoculum of a 1 : 1 ratio of P. gingivalis and T. denticola at 5 × 10(8) or 1 × 10(9) total bacterial cells induced the same level of bone loss as four doses of 1 × 10(10) P. gingivalis cells. Co-inoculation induced strong P. gingivalis-specific T-cell proliferative and interferon-γ-dominant cytokine responses, and induced a strong T. denticola-specific interferon-γ dominant cytokine response. Only at the higher co-inoculum dose of 1 × 10(10) total cells was a T. denticola-specific T-cell proliferative response observed. These data show that P. gingivalis and T. denticola act synergistically to stimulate the host immune response and to induce alveolar bone loss in a murine experimental periodontitis model.
authors: Oral Health CRC, Melbourne Dental School and Bio21 Institute, The University of Melbourne, Melbourne, Vic., Australia.
authors: R K-H
authors: RK
authors: Orth
authors: N M
authors: NM
authors: O'Brien-Simpson
authors: S G
authors: SG
authors: Dashper
authors: E C
authors: EC
authors: Reynolds
mesh_terms: D016301:Alveolar Bone Loss / Q000382:microbiology; D000818:Animals; D055113:Chronic Periodontitis / Q000276:immunology* / Q000382:microbiology*; D004269:DNA, Bacterial / Q000032:analysis; D004195:Disease Models, Animal; D007371:Interferon-gamma / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D007958:Leukocyte Count; D051379:Mice; D008807:Mice, Inbred BALB C; D056265:Microbial Interactions / Q000502:physiology*; D016966:Porphyromonas gingivalis / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology; D048373:Treponema denticola / Q000276:immunology*; D014774:Virulence
chemical_list: D004269:DNA, Bacterial; D015847:Interleukin-4; D007371:Interferon-gamma