Fig. 1

Regulation of immune cells related with MSCs. MSCs interrelate with the regulation of immunoregulatory function of various cells. In terms of T cells, MSCs inhibit the proliferation and activation of T cell. Meanwhile, sums of data address that conventional T cells may transform to regulatory T cells (including CD4 + CD25 + FoxP3 + Treg, CD8 + CD28−Treg and IL-10 + Tr1) given the function of MSCs. Further, with direct contact between cells and transforming the phenotype of natural killer (NK) cells, MSCs has also been proven highly effective in inhibiting the proliferation, cytotoxic effect and the secretion of various cytokines of NK cells. For B cells, MSCs can render the cell cycle stagnant in the G0/G1 phase and trigger the inhibition of B cells proliferation. Moreover, recent studies indicated that MSCs can enlarge the proportion of regulatory B cells (Bregs), such as CD5⁺ B cells, CD19⁺ CD24^highCD38^high B cells, and other Bregs secreting IL-10. Jiang also put forward that human MSCs, as the most efficient one among the antigen-presenting cells (APCs), can inhibit the transformation from monocyte into dendritic cells (DCs). In the meantime, MSCs can inhibit the function of M1 macrophage cells, and induce the transformation of M1 macrophage cells to M2 macrophage cells. Also, MSCs are associated with the suppression of neutrophils