Evaluation of the relationship between mesenchymal stem cells and immune system in in vitro conditions

Determination the immunomodulatory properties of mesenchymal stem cells (MSCs) is necessary before clinical applications. In this study, it was aimed to determine the effect of MSCs on cytokines secreted by immune system cells. Intracellular cytokine levels (Interleukin-4 (IL-4), Interferon-γ (IFNγ), and Interleukin-17 (IL-17)) detected by akım cytometry before and after co-culture between peripheral blood mononuclear cells (PBMCs) and MCSs. At the same time, tumor growth factor (TGF)-β, IL-4, IL-17, IFNγ supernatant cytokine levels were measured by ELISA. In our study, MSCs were isolated from cord blood (CB) and Wharton's Jelly (WJ), and their plastic adherence was observed under the microscope and surface markers (CD44 (100%), CD73 (99.6%), CD90 (100%), CD105 ( 88%)) shown by akım cytometry method. In the study, both CB and WJ-MSCs were used in co-culture MSC/PBMC ratios of 1/5 and 1/10, incubation times of 24 hours and 72 hours. In this study, it was found that PBMCs stimulated with CB-MSCs showed different immunomodulatory properties when the results of co-culture were compared with those before culture. While the intracellular levels of pro-inflammatory cytokines IFNγ and IL-17 increased after both CB-MSC and WJ-MSC and PBMC co-culture, cytokine levels in the supernatant decreased significantly (p<0.05). Among the anti-inflammatory cytokines, IL-4 increased significantly after co-culture, but decreased significantly from the supernatant (p<0.05). The level of TGF-β, which is an anti-inflammatory cytokine, in the supernatant was significantly decreased for both CB-MSC and WJ-MSC (p<0.05). It was reached with the results obtained, the effects of cord blood and WJ-MSC on PBMC were determined and the pro-inflammatory and anti-inflammatory properties of MSCs were determined before and after the application, contributing to the scientific platform.The interaction of MSC and immune system cells initiates a complex process. Therefore, more comprehensive studies are needed to select the most appropriate MSC source and to determine its immunomodulation effects for future clinical researches.