In vivo, MSCs induce T-cell anergy but do not affect TREGs and DCs. T cells from the spleen and lymph nodes of mMSC-treated mice are unresponsive upon anti-CD3, anti-CD3/anti-CD28, and ConA (▪) compared with control mice (▦) (A, ^*P < .05 Mann-Whitney U test). Following in vitro administration of IL-2, T cells from mMSC-treated mice proliferated upon MOG stimulation to levels comparable with T cells from control mice. ▦ indicates MOG-stimulated T cells; ▪, mMSC-treated T cells; and □, IL-2-stimulated mMSC-treated T cells (B). Proliferative responses are expressed as mean CPM ± SD of at least 3 independent experiments. (C) The proportion of CD4⁺CD25⁺ TREGs within CD4⁺CD69^- population of the spleen of control (▦) and MSC-treated (▪) mice. P < .2 by Mann-Whitney U test. Bars represent the mean ± SD percent variation (n = 4) of TREGs. (D) The frequency of costimulatory and class I and class II molecules on CD11c⁺ DCs from the spleen of control mice (▦) and MSC-treated mice (▪). P < .2 by Mann-Whitney U test. Columns represent the mean ± SD percent variation of at least 3 separate experiments. Control mice were immunized with MOG35-55 and treated with intravenous PBS alone.