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[US2-05] Suppressive activity of probiotic bacterial culture supernatant against periodontal pathogenicity of Porphyromonas gingivalis
キーワード：Probiotics、Gingipain、Cytokine induction
Since probiotics improve the balance of microbiota, they might have a preventive effect against periodontal disease, but the suppression mechanism has not been clarified. In order to elucidate it, we investigated the properties of Lactobacilli culture supernatant (LB-cs)against Porphyromonas gingivalis, a representative periodontal pathogen. Culture supernatants of five probiotics candidate strains of Lactobacilli with confirmed antibacterial activity against P. gingivalis (type strain) were neutralized to pH 7 and used as test samples.
In order to examine the effect on the activity of the trypsin-like enzyme Gingipain, which is a periodontal pathogenic factor, P. gingivalis bacterial cell extract was mixed to react with chromogenic synthetic substrates for R-gingipain (RGP) and K-gingipain (KGP) activity. Results showed that all LB-cs inhibited enzymatic activity. It is considered necessary to study the mechanism in future.
Further, for the effects on host immune responsiveness and inflammation induction during infection, normal human epithelial cultured cells and fibroblasts were infected with P. gingivalis, and cytokine (IL-1β, IL -6, TNF-α) production under the presence of LB-cs was detected by ELISA. As a result, though neither P. gingivalis infection nor LPS stimulation showed an increase in inflammatory cytokines in human epithelial cells, the addition of LB-cs increased IL-6 regardless of infection. It is possible that LB-cs activates the immune system of human epithelial cells, which usually have decreased responsiveness to infection with P. gingivalis as a commensal bacterium and promotes elimination of the infection.
On the other hand, in fibroblasts, LB-cs alone did not cause any changes. However IL-6 increased in response to P. gingivalis infection, and the addition of LB-cs inhibited the production of IL-6, indicating a potential for an anti-inflammatory effect.
In order to examine the effect on the activity of the trypsin-like enzyme Gingipain, which is a periodontal pathogenic factor, P. gingivalis bacterial cell extract was mixed to react with chromogenic synthetic substrates for R-gingipain (RGP) and K-gingipain (KGP) activity. Results showed that all LB-cs inhibited enzymatic activity. It is considered necessary to study the mechanism in future.
Further, for the effects on host immune responsiveness and inflammation induction during infection, normal human epithelial cultured cells and fibroblasts were infected with P. gingivalis, and cytokine (IL-1β, IL -6, TNF-α) production under the presence of LB-cs was detected by ELISA. As a result, though neither P. gingivalis infection nor LPS stimulation showed an increase in inflammatory cytokines in human epithelial cells, the addition of LB-cs increased IL-6 regardless of infection. It is possible that LB-cs activates the immune system of human epithelial cells, which usually have decreased responsiveness to infection with P. gingivalis as a commensal bacterium and promotes elimination of the infection.
On the other hand, in fibroblasts, LB-cs alone did not cause any changes. However IL-6 increased in response to P. gingivalis infection, and the addition of LB-cs inhibited the production of IL-6, indicating a potential for an anti-inflammatory effect.