Characterization of the Cellular Responses of Dental Mesenchymal Stem Cells to the Immune System

Introduction: Dental stem cells have gained importance recently and are being used for various purposes in regenerative medicine and dentistry. Although much research has been done to show the various properties of these dental stem cells, the immunomodulatory properties of some of these stem cells are still unknown. This is important considering these cells are being used routinely. Therefore, the aim of this study was to investigate the interactions between the activated immune cells and 3 types of dental-derived mesenchymal stem cells: dental pulp stem cells, stem cells from human exfoliated deciduous teeth, and stem cells of the apical papilla (SCAR). Methods: SCAP, dental pulp stem cells, stem cells from human exfoliated deciduous teeth, and periodontal ligament fibroblasts were cultured, and various assays were performed including a proliferation assay, flow cytometric analysis, lactate dehydrogenase and chromium-51 cytotoxicity assays, and an enzymelinked immunosorbent assay to evaluate the interactions of these dental stem cells when cocultured with either peripheral blood mononuclear cells or natural killer cells. Results: SCAP were less resistant to immune cell-mediated cytotoxicity as seen from the results obtained from the LDH and chromium-51 cytotoxicity assays. The flow cytometric analysis showed a lower resilience of SCAP to cytotoxic compounds. The enzyme-linked immunosorbent assay results demonstrated that the SCAP induced high levels of proinflammatory cytokine secretion compared with the other dental stem cells. Conclusions: SCAR did not perform as well as the other dental stem cells. This could in turn affect their survival and differentiation abilities as well as their functionality. This may be an important aspect to consider when selecting dental stem cells for various regenerative procedures.