Secretion of immunoregulatory cytokines by mesenchymal stem cells

Figure 1 Effect of Interleukin 6 on Th17 formation. IL-6 exerts a dual effect on the generation of Th17 cells. On one side, IL-6 in concert with TGFβ facilitates the generation of this cell population and on the other side, IL-6 inhibits the Th17 cells by inducing the generation of CD8⁺FoxP3⁺ T lymphocytes. TGFβ: Transforming growth factor β.

Figure 2 Mesenchymal stem cells provide an immunoregulatory effect by interactions with dendritic cells and T regulatory cells. Under the influence of cytokines secreted by MSCs and autocrine secreted interleukin-10 (IL-10), the dendritic cells acquire an immature tolerogenic phenotype characterized by a low expression of MHC II and B7 molecules, as well as a higher secretion of IL-10. The secretion of IL-10 induces generation of different subtypes of regulatory T cells which further secrete IL-10 and induce tolerogenic phenotype in dendritic cells. Cytokines secreted from MSCs also lead directly to formation of regulatory T cells. VEGF: Vascular endothelial growth factor; PGE2: Prostaglandin E2; MSCs: Mesenchymal stem cells; IDO: Indoleamine-2, 3-dioxygenase; TGFβ: Transforming growth factor β; DCs: Dendritic cells; IL: Interleukin; CCL: CC chemokine ligand.