## 3 Results
### Impact of MSCs on Expression of Markers Involved in Modulating the Immune Response  
After contact co-culture of CMSCs and activated lymphocytes, the expression of markers involved in the modulation of the immune response was evaluated. The expression of the monitored markers and the intensity of CFSE fluorescence were determined by flow cytometry on a FACS Calibur instrument (Becton Dickinson) using Cellquest software (Becton Dickinson) and FSC Express 5 (De Novo software). The expression of CD90, CD44, CD54, IL-10, TLR4 and TLR3 on CMSCs was evaluated in the presence of lymphocyte. The change of expression was monitored in activated CMSCs after stimulation of _Poly (I:C)_ and co-cultivation with activated PHA lymphocytes and non-activated CMSCs. Surface molecules like chemokine receptors and adhesion molecules mediated direct cell-to-cell communication. The expression of CD90, CD44. CD54, IL-10 and TLR3 and TLR4 receptor expression was followed. CD90 thymocyte differentiation antigen 1 (Thy-1) is the cell surface specific marker for mesenchymal stem cells. CD90 was expressed in most of the cell populations studied. CD44, a cell surface receptor, is considered to be one of the most important adhesion molecules, responsible for activated T-cell mobilizing into the process of inflammation. The expression dynamics of marker CD44 were also monitored. It is a receptor for hyaluronic acid (HA), which is involved in intercellular interactions as well as reactions with collagen molecules. CD44-HA binding facilitates MSC migration and adhesion. Marker CD44 was increased and positive in the _Poly (I:C)_ CMSCs group compared to the observed group of inactivated CMSCs. In the group of inactivated CMSCs, the marker CD44 had a significantly lower expression. CD54 (ICAM-1) is highest expressed molecules on MSCs. ICAM-1 is a transmembrane protein that belongs to the immunoglobulins superfamily [35]. Inflammatory cytokines can mediate the interaction of ICAM-1 and LFA-1 ligand and subsequently promote leukocyte migration to the site of tissue or organ damage. Activated CMSCs had significantly higher CD54 expression compared to the lower CD54 expression of non-activated cells. _Poly (I:C)_ acts as a TLR3 activator on cells, an analogue of double-stranded viral RNA. MSCs react dynamically to molecules of the surrounding microenvironment and, after activation, acquire strong immunomodulatory properties. Based on these observations, a type of polarization of MSCs on MSC1 and MSC2 associated with TLR4 activation, or TLR3, was proposed. Figure 7: **(a)** Compared proliferation of three types of groups of CFSE labeled PHA lymphocytes. The highest fluorescence was observed on the first day (0 day lymphocytes (LY)). After 4 days the fluorescence was compared in the three experimental groups. Significant differences between the groups: LY/CMSCs _Poly (I:C)_, LY/CMSCs and group lymphocytes alone cultured was detected. LY/CMSC _Poly (I:C)_ (\(p=0.0028\)) and lymphocytes LY/CMSC (\(p=0.0243\)) and **(b)** Post hoc analysis of the experimental group of lymphocytes, CMSCs (_Poly I:C)_ (\(p=0.0028\)) and lymphocytes with CMSCs (\(p=0.0243\)). Comparison of the \(\Delta\) proliferating fraction (\(\Delta\)PF) of groups \(\Delta\)PF1 CMSCs _Poly (I:C)_ group and \(\Delta\)PF2 (CMSCs). Histograms represent mean \(\pm\) S.E of seven independent experiments. MSC1 with a pro-inflammatory phenotype and activated TLR4 are characterized by the secretion of inflammatory mediators, IL-6 and IL-8. TLR3-activated MSC2s produce the anti-inflammatory mediators IL-10 and IL-1 RA, which can inhibit T cell proliferation through prostaglandin E2 (PGE2) and IDO expression [36]. MSCs that are active through TLR3 have a more effective ability to activate their adhesive properties and bind to leukocytes. Low expression of TLR3 and TLR4 was observed on the CMSCs after _Poly (I:C)_ activation and in the group without activation. MSCs produce IL-10, which acts as a broad-spectrum, anti-inflammatory cytokine. Effects on IL-1 function.