Immunosuppressive properties of MSC-derived EVs.
EVs were purified from resting and primed MSCs and added to unfractionated PBMCs or sorted-T, B and NK cells that were activated by specific stimuli (1 × 104:3 × 106 IEC:EV ratio). At the end of co-cultures, the cells were harvested and IEC proliferation was assessed by FACS analysis. CFSE fluorescence was analyzed after 4 days for PBMCs, T and B cells (a–c, respectively), while for NK cells (d) the fluorescence was analyzed after 6 days of co-culture. The results are expressed as relative proliferation percentage of IECs, normalized to IEC cultured alone (100%). Error bars represented mean ± SEM of six for PBMCs and five for sorted-T, NK cells and B cells independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001.