Mesenchymal stem cells have the capacity to maintain immune homeostasis and prevent autoimmunity. We recently reported that human-derived gingival mesenchymal stem cells (GMSCs) have strong capacity to suppress immune responses and T cell-mediated collagen-induced arthritis in animals. However, it is unclear whether these cells can suppress human T cell-mediated diseases. Here, we used a xenogenic GVHD model in the NOD/SCID mouse, which is a useful preclinical construct for evaluating the therapeutic and translational potential of this approach for applications in human disease. We found that GMSCs potently suppressed the proliferation of PBMC and T cells in vitro. Co-transfer of GMSC with human PBMC significantly suppressed human cell engraftment and markedly prolonged the mouse survival. Moreover, we demonstrated that GMSCs inhibited human PBMC-initiated xenogenic responses via CD39/CD73/adenosine and IDO signals. These findings suggest the potential for GMSCs to suppress human immune responses in immune system-mediated diseases, offering a potential clinical option to be used for modulating GVHD and autoimmune diseases.
Keywords: CD39; CD73; GVHD; adenosine; gingival mesenchymal stem cell; immune regulation; indoleamine 2,3-dioxygenase.