The Role of Mesenchymal Stem Cells in Immune Response

Mesenchymal stromal cells (MSCs) represent a cell population which displays adherent properties, be able to self-renew and have multilineage differentiation capabilities. Recently, it is found that MSCs can exert strong immunomodulatory function in numerous studies. Overall, MSCs can exert a suppressive function on nearly all the cells in the whole immune system, including T lymphocytes, B lymphocytes, natural killer cells and dendritic cells, yet they can also play a positive role in the proliferation and the differentiation of some kind of immune cells. So far there are several mechanisms considered to be responsible for the immune regulatory function of MSCs, for example, indoleamine 2, 3, - dioxygenase (IDO) -induced depletion of tryptophan from the lymphocyte environment, the secretion of prostaglandin E2 and matrix metalloproteinases (MMP), the expression of insulin-like growth factor (IGF)-binding proteins, inducible nitric oxide synthase (iNOS), human leukocyte antigen-G (HLA-G) protein and the recruitment of regulatory T cells. Thus MSCs' immunosuppressive properties encourage a possible use of these cells to therapy immune disorders. This paper will review the MSCs' impact on the generation, differentiation and function of the immune cells, as well as the underlying mechanisms