Induction of inflammatory cytokine and cyclooxygenase-2 mRNA expression by secreted substances from oral streptococci

Abstract

Induction of inflammatory cytokine and cyclooxygenase (COX)-2 mRNA expression in human peripheral blood mononuclear cells (PBMC) was studied with the culture supernatants of eight species of oral streptococci using reverse transcription-polymerase chain reaction. The mRNA levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in PBMC were increased after incubation with the culture supernatants of Streptococcus anginosus and S. constellatus. The level of IL-1β mRNA was increased significantly with the culture supernatants of S.anginosus, S.constellatus and S.gordonii. S. anginosus culture supernatant also demonstrated the induction of COX-2 mRNA expression and prostagrandin E₂ production in PBMC culture medium. These results suggest that S.anginosus and S.constellatus produce bioactive substances inducing the mRNA expression of inflammatory cytokines and COX-2 in immunocytes.