In vitro evaluation of the immunosuppressive potential of MSCs by quantification of soluble mediators.

<p>A) Inhibition of T cell proliferation following co-culture with MSCs. Allogeneic splenocytes (10⁵ cells) were incubated for three days with ConA and when indicated, 5×10⁴ wildtype (wt) C57Bl/6 or MSCs isolated from iNOS^−/−, IL-6^−/− knock-out C57Bl/6 mice or DBA/1 MSCs were added. Results are expressed as the percentage of ConA-induced proliferation which was assigned the value of 100% ± SEM (n = 3). B) Quantification of NO₂ secretion using a modified Griess reagent. C) Quantification of IL-6 secretion by ELISA. D) Quantification of PGE₂ secretion by ELISA. Levels of the various soluble mediators were quantified in supernatants of the proliferative assays performed in A) after stimulation with ConA. Parallel assays were performed on cells incubated in the same conditions with the addition of inhibitors specific for NO₂ (L-NAME) or PGE₂ (indomethacin; Indo). Results are expressed as the mean of 3 independent experiments ± SEM; p values referred to ConA-activated samples (black histograms), if not indicated (*: p<0.05).