Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) mirror immunomodulatory properties as mesenchymal stem cells (MSCs). We isolated human umbilical cord-derived MSC-EVs (HUC-MSC-EVS) by PEG-based precipitation and characterized the EV preparations. Peripheral blood mononuclear cells (PBMCs) were treated with HUC-MSC-EVs and tested whether MSC-EVs could modulate T-cell proliferation and cytokine secretion. Our data demonstrate that HUC-MSC-EVs inhibit PBMC proliferation and modulation in Th1/Th2 and Th17-driven cytokine expression. EV-driven modulation also reduces matrix metalloprotein-9 (MMPs), confirmed by gelatin zymography. Thus, HUC-MSC-EVs would boost T-cell responses and provide novel therapeutic options for inflammatory diseases. © 2022 IEEE.