Comparing the immunoregulatory effects of stem cells from human exfoliated deciduous teeth and bone marrow-derived mesenchymal stem cells.

Stem cells from human exfoliated deciduous teeth (SHED) have been introduced recently and possess characteristics similar to mesenchymal stem cells (MSCs). Because of their convenient accessibility and safety of harvest, SHED can be a preferable source for the ever-increasing MSCs' applications  While they are new, their immunoproperties have not been adequately studied. In this study, we aimed to explore the effect of SHED on T lymphocytes and compare it to conventional MSCs (BMMSCs).At first the isolated T lymphocytes were activated specifically/nonspecifically in vitro and cocultured with SHED or BMMSCs under the same conditions, subsequently their proliferation and cytokine secretion (IL-2 and IFN-γ) were measured.In our experiment, BMMSCs and SHED inhibit the proliferation and cytokine production of both PHA and alloantigen stimulated T lymphocytes in a dose-dependent manner. In direct and indirect contact to T lymphocytes, the inhibition of BMMSCs (but not of SHED) was significantly different The cytokine production from activated T cells was affected differently by two types of MSCs. The inhibition decreased by the separation of lymphocytes and MSCs by a semipermeable membrane, but it was not abolished.This study showed that SHED suppress the activation of human T lymphocytes in vitro like other MSCs. Compared to BMMSCs, this suppression was alleviated. In the equal conditions, the pattern of immune-modulation of BMMSCs and SHED was different, suggesting that SHED do not exert the exact mechanisms of BMMSCs' immunosuppression., This finding should be verified by further studies focused on the detailed mechanisms  of the immunomodulation of SHED and also BMMSCs.