gingivalis (103 CFU) into the gums of ICR mice everyday for 3 days induced greater gum swelling than injection of individual bacterium (data not shown), suggesting that bacterial co-aggregation exacerbates gum inflammation. To examine if FomA contributes to the exacerbation of gum inflammation, F. nucleatum (4 × 108 CFU) was neutralized with either anti-FomA or anti-GFP serum [2.5% (v/v)] prior to mixing with P. gingivalis (103 CFU). To induce gum inflammation, this bacterial mixture was injected into the gums of the lower incisors of naïve ICR mice everyday for 3 days. buy Nutlin-3 Three days after injection, the severity of gum swelling was recorded for 4

days. Injection of P. gingivalis with anti-GFP serum-neutralized F. nucleatum induced a swollen gum with the volume ranging Depsipeptide chemical structure from 2.95 to 7.36 mm3. The greatest degree of swelling (7.36 ± 0.12 mm3) was observed on the day 3 after recording ( Fig. 4A and B). The gum swelling was significantly suppressed when the gum was injected with P. gingivalis along with anti-FomA serum-neutralized F. nucleatum. These results reveal the essential role of FomA in bacterial co-aggregation-induced gum inflammation and further supported FomA as a potential therapeutic

target for treatment of bacterial co-aggregation-associated diseases. To evaluate if FomA can be a valuable target for the development of vaccines against periodontal infection, mice were immunized with UV-inactivated-E. coli BL21(DE3) FomA or GFP for 9 weeks. To induce inflammation, the gums of lower incisors in the immunized mice were challenged with live F. nucleatum (4 × 108 CFU) alone, P. gingivalis (103 CFU) alone, and F. nucleatum plus P. gingivalis (4 × 108/103 CFU) everyday for 3 days. The severity of bacteria-induced gum swellings was measured daily for 4

days after 3-day challenge. Vaccination with E. coli BL21(DE3) FomA or GFP did not make a significant difference in of the amount of gum swelling induced by the injection of F. nucleatum alone or P. gingivalis alone ( Fig. 5A). However, compared to the mice immunized with E. coli BL21(DE3) GFP, the amount of the gum swelling induced by co-injection of F. nucleatum and P. gingivalis was considerably attenuated in the mice immunized with E. coli BL21(DE3) FomA. Histological examination by H&E staining illustrated the gum inflammation with thickened gum epithelium and gramulomatsis. In addition, there was greater inflammation caused by bacterial co-injection in the GFP-immunized mice than in the FomA-immunized mice ( Fig. 5B). Previous studies have shown that the induction of pro-inflammatory cytokines plays a crucial role in the pathogenesis of periodontal infection [30]. To determine whether immunization with FomA alters the level of bacterial co-injection-induced pro-inflammatory cytokines, MIP-2 cytokine in swollen gums was quantified by ELISA. On day 2 following a 3-day challenge with both F. nucleatum and P. gingivalis, a significant elevation in the level of MIP-2 (15,528.88 ± 68.