The role of soluble factors in MSC-mediated immunoregulation

It is known that the immunomodulatory functions of mesenchymal stem cells (MSCs) are realized through interdependent immunoregulatory network. Recently, researchers have increasingly been searching for soluble factors and molecules secreted in immunoprivileged organs and tissues and allowing to avoid the immune response. Such molecules can be galectin-1 and HLAG, which expressed on the trophoblast and ensure the development of immunotolerance.The objective of this study was a comparative analysis of the production of soluble HLA-G and galectin-1 molecules, as well as interleukin-10 by intact mesenchymal stem cells and during their co-cultivation with peripheral blood lymphocytes of recipients of allogeneic hematopoietic stem cells.As a result of the study, it was found that for the release of the soluble form of HLA-G and, consequently, the implementation of the immunomodulatory properties of MSCs, interaction between MSCs and peripheral blood lymphocytes is necessary. At the same time, the intercellular interaction of MSCs and lymphocytes did not promote increased production of galectin-1, the main contribution to the production of which in mixed cultures was made by MSCs. The level of soluble HLA-G molecule depended on the concentration of IL-10 in the culture. The revealed patterns indicate that the choice of a biomedical cell product based on MSCs should be carried out taking into account the production of soluble factors characterizing their immunoregulatory potential, which can ultimately increase the effectiveness of cell therapy.