Human MSCs inhibited the initial yield of DCs from monocytes reversibly. Using the transwell chamber system separating monocytes (top row) from MSCs (bottom row), monocytes that have been cultured with GM-CSF plus IL-4 for 7 days in the presence of MSCs (at a ratio of 1:10) were collected and then induced by GM-CSF, IL-4, and LPS for 7 days. Percentage of cells positive for the indicated markers is shown. Results are representative of 3 independent experiments. Horizontal bars indicate the positive region; the corresponding percentage is shown above each bar.