Immunomodulation by mesenchymal stem cells: Interplay between mesenchymal stem cells and regulatory lymphocytes

Figure 2 Mesenchymal stem cells-mediated regulatory T cell induction. MSCs induce T_reg cells through soluble mediators stimulation, cell-cell interaction, and modulation of antigen-presenting cells. Under inflammatory environment, MSCs secretes TGF-β1, PGE2 and IDO to facilitate the differentiation of naïve T cells to Foxp3⁺T_reg cells. MSCs can also interact with Th17 cells by direct contact via CD54 and C11a/CD18. With the presence of PGE2, differentiated Th17 cells can be converted to functional Foxp3⁺T_reg cells. MSCs can increase the secretion of IL-10 by antigen presenting cells, which will then induce Tr1 cells differentiation. MSCs: Mesenchymal stem cells; IL: Interleukin; T_reg: Regulatory T; TGF: Transforming growth factor; PGE2: Prostaglandin E2; IDO: Indoleamine 2,3-dioxygenase.