Pretreatment of Mesenchymal Stem Cells With Leishmania major Soluble Antigens Induce Anti-Inflammatory Properties in Mouse Peritoneal Macrophages.

Recent studies have demonstrated the influential role of microbial stimulus in characteristics and immunomodulatory effects of mesenchymal stem cells (MSCs). Due to the migration of MSCs to infection site, it is of importance to understand the interaction of microbial ligands with MSCs in order to clarify the positive or negative role of MSCs in the control of infection. In this research, we assess leishmanial soluble antigen (LSA)-primed MSCs on macrophage immune responses to lipopolysaccharide (LPS). For this purpose, the effects of both conditioned media (CM) and cell-cell contact of LSA primed MSCs were determined on macrophage responses to LPS. According to the obtained results, MSC-treated macrophages demonstrated an alternatively activated macrophages with higher levels of interleukin-10 (IL-10) and transforming growth factor-alpha (TNF-α) and lower levels of IL-6 and nitric oxide (NO) production as compared to the controls. In addition, phagocytosis of apoptotic thymocytes was induced in MSC-treated macrophages. In conclusion, it seems that MSCs trigger an anti-inflammatory phenotype in macrophages at Leishmania infected sites in order to enhance the induction of immune regulatory cells and clearance of apoptotic cells. J. Cell. Biochem. 118: 2764-2779, 2017. © 2017 Wiley Periodicals, Inc.