Figure 2

Mesenchymal stem cells (MSCs) inhibit the anti-CD3-induced proliferation of CD4⁺ T cells in vitro. (a) CD4⁺ T cells (5 × 10⁴ cells) and accessory cells (5 × 10⁴ cells) were incubated with 3 μg/ml anti-CD3 antibody and the indicated numbers of mitomycin c-treated wild-type or interferon-gamma receptor knockout (IFN-γR KO) MSCs for 72 hours and pulsed for the last 16 hours with 1 μCi of [³H]TdR. The percentage inhibition (100 × [(radioactivity in cultures without MSCs -- radioactivity in cultures with MSCs)/radioactivity in cultures without MSCs]) by increasing numbers of MSCs is shown. Each result represents the mean of four cultures ± standard error of the mean (SEM). Results are representative of two independent experiments. * P < 0.05 for comparison with wild-type MSCs (Mann-Whitney U test). (b) Carboxyfluorescein succinimidyl ester (CFSE)-labeled CD4⁺ T cells (5 × 10⁴ cells) and accessory cells (5 × 10⁴ cells) were incubated with 3 μg/ml anti-CD3 antibody and the indicated numbers of mitomycin c-treated wild-type or IFN-γR KO MSCs for 72 hours. The proliferation of CD4⁺ T cells was analyzed by detection of CFSE dilution by flow cytometry. The percentage inhibition (100 × [(percentage of proliferating CD4⁺ cells not treated with MSCs -- percentage of proliferating CD4⁺ cells treated with MSCs)/percentage of proliferating CD4⁺ cells not treated with MSCs]) by increasing numbers of MSCs is shown. Each result represents the mean of three cultures ± SEM. Results are representative of two independent experiments. * P < 0.05 for comparison with wild-type MSCs (Mann-Whitney U test).