Figure 1

Overview of the interactions between mesenchymal stromal cells (MSCs) and immune cells. MSCs secrete cytokines (including transforming growth factor β, hepatocyte growth factor, IL-6, IL-7), chemokines (CCL2, IL-8) and prostaglandins (prostaglandin-E2), and express proliferation inhibitory cell surface molecules (programmed death ligand 1, Fas ligand) and metabolic enzymes (indoleamine 2,3-dioxygenase, CD73) that target immune cells in various ways. APC, antigen-presenting cell; NK, natural killer; TLR, Toll-like receptor.