Figure 3.

Suppression of B-cell proliferation and IgE production by cMSCs. (a) Purified B cells from Balb/c mice were stimulated with either LPS or anti-CD40 antibodies in the presence of IL-4. Cells were cultured for 3 days. During the final 16 h culture period, 1 μCi ³H-thymidine was added and B-cell proliferation was determined by thymidine incorporation. The cMSCs slightly inhibited B-cell proliferation in a number-dependent manner. (b) To measure IgE production, cells were cultured for 5 days and IgE in culture media was measured by ELISA. IgE production was inhibited by cMSCs in a cell–cell contact-dependent manner. (c) To measure IgE-producing B cells, cells were cultured for 3 days. During the final 6 h culture period, brefeldin A was added. Intracellular IgE production was detected by flow cytometry. IgE-producing B cells were reduced by cMSCs. Similar results were obtained in two to three independent experiments. M, cMSCs; B, B cells; CC, co-culture; TW, Transwell, *P<0.001