Comparison of the Immunological Responses in Mice Sensitized with Live Bacteria of Either Fusobacterium nucleatum or Porphyromonas gingivalis and Its Bactericidal Effect

Abstract

The immunological responses induced by Porphyromonas gingivalis (Pg) and Fusobacterium nucleatum (Fn) in mice were compared. SPF ICR immune mice were obtained by 3 injections with either Pg or Fn. Two weeks later each bacteria was administered to immunized mice and mice were assayed for cell numbers in exudates, antibody titer, cytokine production, expression of cytokine receptors, and the elimination of the bacteria. The total cell numbers in Fn immunized, then Fn challenged, mice were 1.6 times that of mice challenged with Pg. High IgG antibody titers were detected in Pg immunized mice and IgM antibody predominated in Fn immunized mice.TNFα production was higher in the abdomen of Pg immunized mice than in serum. IL-1β levels were the same in both Fn and Pg challenged mice. IFNγ production was significantly higher in Fn than Pg-immunized mice. Expression of CXCR-1 and CXCR-3 mRNA was significantly higher in Fn than Pg-immunized mice. The elimination effect of the bacteria in the abdominal cavity was remarkable after Fn but not in Pg immunization. Fn immunized mice were more effective in eliminating Pg in the abdomen, suggesting the macrophage activation via Th1 may play a part in protection from periodontitis.