title: The role of coaggregation between Porphyromonas gingivalis and Fusobacterium nucleatum on the host response to mixed infection.
abstract: OBJECTIVE
  To evaluate the role of coaggregation between Porphyromonas gingivalis and Fusobacterium nucleatum on the virulence of the mixed infection in mice.
  
  
  METHODS
  Inhibition of coaggregation was carried out using lactose. In vitro, inhibition of coaggregation was verified using a coaggregation assay. In vivo, the virulence of the mixed infection, with and without coaggregation, was examined in a model of experimental periodontitis in mice. The local host response to the mixed infection, with or without coaggregation, was examined using the subcutaneous chamber model of infection.
  
  
  RESULTS
  Lactose inhibited the coaggregation between P. gingivalis and F. nucleatum at all the tested concentrations (1-0.0625 M). Surprisingly, the addition of lactose to the mixed infection increased the severity of experimental periodontitis (as measured by alveolar bone loss) compared with mixed infection with coaggregating bacteria. The addition of lactose to the mixed infection resulted in mild attenuation of TNFα and IL-1β levels. In addition, inhibition of coaggregation resulted in inhibition of the phagocytosis of F. nucleatum and augmentation of the phagocytosis of P. gingivalis.
  
  
  CONCLUSIONS
  The ability of P. gingivalis and F. nucleatum to coaggregate may limit their ability to induce experimental periodontitis in a mixed infection model. Moreover, there is a shift in the phagocytosis pattern of the bacteria with the annulment of coaggregeaiton, with a reduction in F. nucleatum phagocytosis and amplification of P. gingivalis phagocytosis. The increased virulence of the mixed infection without coaggregation may surprisingly lay in the sustention of F. nucleatum in the infected sites.
authors.affiliation: Department of Periodontology, The Hebrew University-Hadassah Medical center, Jerusalem, Israel. polak@cc.huji.ac.il
authors.forename: David
authors.initials: D
authors.lastname: Polak
authors.forename: Lior
authors.initials: L
authors.lastname: Shapira
authors.forename: Ervin I
authors.initials: EI
authors.lastname: Weiss
authors.forename: Yael
authors.initials: Y
authors.lastname: Houri-Haddad
mesh_terms: D016301:Alveolar Bone Loss / Q000382:microbiology; D000818:Animals; D001422:Bacterial Adhesion / Q000187:drug effects / Q000502:physiology*; D001431:Bacteriological Techniques; D016866:Bacteroidaceae Infections / Q000382:microbiology*; D060085:Coinfection / Q000382:microbiology*; D015194:Diffusion Chambers, Culture; D005260:Female; D005674:Fusobacterium Infections / Q000382:microbiology*; D016967:Fusobacterium nucleatum / Q000187:drug effects / Q000472:pathogenicity*; D054884:Host-Pathogen Interactions / Q000502:physiology; D053583:Interleukin-1beta / Q000032:analysis; D007785:Lactose / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D010518:Periodontitis / Q000382:microbiology*; D010587:Phagocytosis / Q000502:physiology; D016966:Porphyromonas gingivalis / Q000187:drug effects / Q000472:pathogenicity*; D015163:Superinfection / Q000382:microbiology; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis; D014774:Virulence; D055114:X-Ray Microtomography
chemical_list: D053583:Interleukin-1beta; D014409:Tumor Necrosis Factor-alpha; D007785:Lactose