Human dental pulp stem cells: a sanctuary for relapsingBartonella quintana

Abstract

ABSTRACTBartonella quintanais a facultative intracellular bacterium responsible for relapsing fever, an example of non-sterilizing immunity. The cellular sanctuary ofB. quintanain-between febrile relapses remains unknown but repeated detection ofB. quintanain dental pulp specimens suggested long-term half-life dental pulp stem cells (DPSCs) as candidates. As the capacity of DPSCs to internalize microscopic particles was unknown, we confirmed that DPSCs internalizedB. quintanabacteria: Gimenez staining and fluorescence microscopy localizedB. quintanabacteria inside DPSCs and this internalization did not affect the cellular multiplication of DPSCs during a one-month follow-up despite the increase in the bacterial load.B. quintana-infected DPSCs did not produce Tumor Necrosis Factor-α whereas an important production of Monocytes Chemoattractant Protein-1 was observed. These unprecedented observations suggested the possibility that DPSCs were shelters for the long-term persistence ofB. quintanain the host, warranting further experimental and clinical investigations.