Mesenchymal Stem Cells: Interactions with Immune Cells and Immunosuppressive-Immunomodulatory Properties

Abstract Background and Objectives Recently, mesenchymal stem cells have attracted much attention in regenerative medicine and cell-based therapies. Mesenchymal stem cells are used in regenerative medicine mainly based on their capacity to differentiate into several cell lineages, low immunogenicity, and in particular their anti-inflammatory and immunosuppressive-immunomodulatory properties.   Materials and Methods The present manuscript, by reviewing more than 150 recent published articles, introduces the latest information regarding the anti-inflammatory and immunosuppressive-immunomodulatory properties of the mesenchymal stem cells.   Results The fibroblast-like mesenchymal stem cells can be isolated from various sources such as bone marrow, adipose tissue, skeletal muscle, Wharton jelly, umbilical cord, placenta, and amniotic fluid. The immunomodulatory properties of mesenchymal stem cells result from their interactions with innate and adaptive immune systems to inhibit immune cells. Such an inhibitory function is due to the interaction of these cells with immune cells through direct cell-cell contact or via paracrine secretory factors. The composition of these secretions or secretom of these cells includes various components such as growth factors, cytokines, chemokines, anti-inflammatory mediators and exosomes. Many in vivo studies in animal models have demonstrated that the ability of mesenchymal stem cells to regenerate and repair tissues is more attributed to their immunosuppressive-immunomodulatory function rather than their proliferative properties.   Conclusions  Therefore, understanding the mechanisms establishing the interactions of these cells with immune system would be important for their use as a promising therapeutic approach in the future for treatment of immunological diseases as well as in the field of regenerative medicine.