Functional capacity of rATG-expanded Tregs. (A) Proliferation of PBMCs inhibited by rATG-expanded T cells was measured by the BrdU incorporation ELISA method. (B) CD4⁺CD25⁺ T cells isolated from rATG-treated PBMCs inhibited T-cell response in a dose-dependent manner. Results are expressed as the percentage determined by comparing proliferation induced by rATG or hATG to responder PBMCs stimulated with CD3/CD28 mAb alone. Bars represent mean plus or minus SD of 3 separate experiments.