Human Dental Pulp Stem Cells Suppress Alloantigen-induced Immunity by Stimulating T Cells to Release Transforming Growth Factor Beta. 
Human dental pulp stem cells (hDPSCs) are ideal candidates for regenerating damaged dental tissue.  To examine the possibility that hDPSCs may be used to regenerate pulp, we tested their in vitro effects on acute allogeneic immune responses.  A peripheral blood mononuclear cell (PBMC) proliferation assay and immunoglobulin (Ig) production assay were performed to evaluate the immunosuppressive properties of hDPSCs.  The mixed lymphocyte reaction was suppressed by incubation with hDPSCs.  Transforming growth factor beta (TGF-β) was the major soluble factor responsible for inhibiting the allogeneic proliferation of PBMCs.  The production of IgM and IgG by allogeneic activation of responder B lymphocytes was also completely abrogated by TGF-β released from hDPSCs via interferon gamma in response to activation of the responder T lymphocytes.  hDPSCs inhibit acute allogeneic immune responses by their release of TGF-β as a result of allogeneic stimulation of T lymphocytes.  This study provides an insight into the potential clinical use of hDPSCs for allogeneic transplantation.