Figure 2.

Allo-response and immunosuppressive capacity of activated MSCs. (A) A mixed lymphocyte reaction (MLR) was performed. Proliferation of CFSE-labeled PBLs from two independent donors (dark and light bar) in a co-culture with HLA-mismatched MSCs (blue bars), or MSC-γ (red bars). HLA-mismatched mDCs (green bars) were used as a positive control of proliferation of allo-reactive T-cells. Proliferation was calculated relative to CD3/CD28 bead induced proliferation of PBLs (set to 100%) (N = 2). (B) A suppression assay was performed with three independent PBL donors. Proliferation of CFSE-labeled PBLs was induced by CD3/CD28 beads. Histograms represent proliferation of CD4 T-cells when stimulated with CD3/CD28 beads alone (gray histograms), or in the presence of non-activated MSC (blue histograms), or MSC-γ (red histograms). The panels represent proliferation of three different allo-geneic PBL donors in co-culture with one MSC donor. (C) This experiment was repeated three times, each time with different PBL and MSC donors. The bar graph shows the proliferation index of different allogeneic CFSE-labeled PBL donors, activated by CD3/CD28 beads, cultured with no MSC (gray), MSC (blue), and MSC-γ (red). The proliferation index is on gated CD4 T-cells. The data are presented as mean ± SD of three different MSC donors each cocultured with different allogeneic PBL donors in three independent experiments. ^**p = 0.008; ^****p < 0.0001, one-way ANOVA with Tukey's correction for multiple comparisons. PBL, peripheral blood lymphocyte.