FIG. 1.

Mesenchymal stromal cells (MSCs) inhibit CD4⁺ T-cell proliferation, but do not induce a classical Treg phenotype. Total peripheral blood mononuclear cells (PBMCs) were tested upon stimulation with allogeneic PBMCs in the presence and absence of MSCs. (A) CD4⁺ T-cell proliferation, analyzed by CFSE dilution, was inhibited by the presence of MSCs. (B) CD4⁺ T-cells were also analyzed for the presence of Tregs (CD4⁺ CD25⁺ CD127⁻ FoxP3⁺ cells). (C) CD69 expression was analyzed on CD4⁺ FoxP3⁻ CD25⁻ cells. n=4. *p=0.05, **p=0.01, and ***p=0.0005 (paired t-test). CFSE, 5-(and 6)-carboxyfluorescein diacetate succinimidyl ester.