IADR Abstract Archives
Enterococcus faecalis; the endodontic pathogen and its diverse effects on monocyte derivatives.
Objectives: The present study investigated how E. faecalis infection affects the differentiation, phenotype and cytokine secretion profile of dendritic cells and macrophages.
Methods: Murine bone marrow-derived stem cells were co-cultured with E. faecalis then one group was exposed to GM-CSF/IL4 to allow differentiation of dendritic cells while other group exposed to M-CSF to allow differentiation of macrophages. localization of the bacteria inside th cells was visualized usnig Confocal Laser Scanning Microscopy and Transmission Electron Microscopy. The cells were analyzed using MACSQuant® Analyzer Flow Cytometer to detect phenotypic changes. Gene expression was analyzed with reverse transcriptase-polymerase chain reaction (RT-PCR).
Results: Enterococcus faecalis did not inhibit cellular differentiation and was identified within the cells involved in the process of binary fission. Although the viability of dendritic cells was not affected by E. faecalis, it was enhanced in macrophages. Accessory molecules (MHCII, CD80, CD86) and anti-inflammatory cytokine TGFB1 were suppressed in E. faecalis-induced dendritic cells while IL1B, TNF alpha and IL12 levels were upregulated. A different profile was noticed in macrophages where there is upregulation of CD38 and IRF5 proteins, indicators of M1-like polarization. These M1-like macrophages expressed an aberrant cytokine mRNA profile, with reduction in pro-inflammatory cytokines IL1B and IL12 and increase in regulatory cytokine IL10. No changes in TNF alpha or TGFB1 was detected.
Conclusions: Enterococcus faecalis interacts with the immune cells in a sophisticated manner that enhances its own survival and resists the bacterial clearance. The results of this study may explain to some extent failure of the body’s immune system to eliminate the bacteria following unsuccessful root canal treatment. Knowledge of how E. faecalis alters the immune cells may aid in modifying conventional treatments to eradicate these persistent infections.
Methods: Murine bone marrow-derived stem cells were co-cultured with E. faecalis then one group was exposed to GM-CSF/IL4 to allow differentiation of dendritic cells while other group exposed to M-CSF to allow differentiation of macrophages. localization of the bacteria inside th cells was visualized usnig Confocal Laser Scanning Microscopy and Transmission Electron Microscopy. The cells were analyzed using MACSQuant® Analyzer Flow Cytometer to detect phenotypic changes. Gene expression was analyzed with reverse transcriptase-polymerase chain reaction (RT-PCR).
Results: Enterococcus faecalis did not inhibit cellular differentiation and was identified within the cells involved in the process of binary fission. Although the viability of dendritic cells was not affected by E. faecalis, it was enhanced in macrophages. Accessory molecules (MHCII, CD80, CD86) and anti-inflammatory cytokine TGFB1 were suppressed in E. faecalis-induced dendritic cells while IL1B, TNF alpha and IL12 levels were upregulated. A different profile was noticed in macrophages where there is upregulation of CD38 and IRF5 proteins, indicators of M1-like polarization. These M1-like macrophages expressed an aberrant cytokine mRNA profile, with reduction in pro-inflammatory cytokines IL1B and IL12 and increase in regulatory cytokine IL10. No changes in TNF alpha or TGFB1 was detected.
Conclusions: Enterococcus faecalis interacts with the immune cells in a sophisticated manner that enhances its own survival and resists the bacterial clearance. The results of this study may explain to some extent failure of the body’s immune system to eliminate the bacteria following unsuccessful root canal treatment. Knowledge of how E. faecalis alters the immune cells may aid in modifying conventional treatments to eradicate these persistent infections.
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