Figure 3.

Immunosuppressive properties of MSCs. Damaged tissues are always accompanied by infiltration of immune cells and MSCs. Inflammation triggers the production of high levels of chemokines and adhesion molecules in MSCs, including CXCR3 ligands, CCR5 ligands, ICAM-1 and VCAM-1. These molecules induce the accumulation of immune cells in close association with MSCs, whereby high concentrations of NO (in murine MSCs) or depletion of tryptophan (in human MSCs) leads to the inhibition of immune cells. Other immunosuppressive factors such as IL-10, TSG6, IL-6, LIF, PGE2, HO-1 and truncated CCL2 could also affect immune cell activation, proliferation and functions