Regulation of suppressing and activating effects of mesenchymal stem cells on the encephalitogenic potential of MBP68–86-specific lymphocytes

Mesenchymal stem cells (MSCs) possess immunosuppressive potential and are proposed as a tool for cell therapy, however under certain circumstance they could change to become immunostimulating. It is therefore of great importance to better understand the MSCs' immune plasticity. Here we used different doses of MSCs to co-culture with MBP68–86-specific T cells and found that MSCs exerted a suppressive effect on the encephalitogenic ability of MBP68–86-specific T cells at high MSC density (MSC/effector ratio ≥ 1:10). Whereas at lower MSC/effector ratios (≤ 1:50), MSCs shifted towards stimulatory activity. Thus the limited amounts of MSCs for application should be considered.