MSCs alter cytokine secretion from DC1 and DC2. Human MSCs were cocultured with (A) mature monocytic dendritic cells (DC1) or (B) mature plasmacytoid dendritic cells (DC2) in the presence or absence of inflammatory stimulus LPS (1 ng/mL). When hMSCs were present, there was a more than 50% decrease in the secretion of TNF-α by activated DC1 (TNF-α levels secreted by LPS-treated DC1 = 100%). The coculture of hMSCs with DC2 consistently increased the secretion of IL-10 by more than 100% (IL-10 levels secreted by LPS-treated DC1 = 100%). The graphs represent the cytokine levels (mean percent change ± SD) from 5 independent experiments in the presence or absence of hMSCs.