• Porphyromonas asaccharolytica;
  • Bacteroides fragilis;
  • OmpA;
  • cytokine


OmpA proteins from Gram-negative anaerobes Porphyromonas asaccharolytica and Bacteroides fragilis induced release and expression of IL-1α, tumor necrosis factor (TNF)-α, IFN-γ, IL-6, and IL-10 from murine splenocytes in vitro in a dose-dependent fashion. The release of the cytokines induced by B. fragilis Bf-OmpA was at much lower levels compared with P. asaccharolytica Omp-PA; Bf-OmpA did not induce release of IL-10. Omp-PA and Bf-OmpA were able to upregulate mRNA expression of the tested cytokines. The results obtained with refolded Bf-OmpA were similar to those with native Bf-OmpA. The data presented in this research demonstrate for the first time that Omps from anaerobic bacteria can induce the release of cytokines, suggesting that Omp-PA and Bf-OmpA may play important roles in the pathogenic processes of these bacteria.