Suppressive activity of CD4⁺CD25⁺FoxP3⁺ Tr cells. Diabetic Balb/c mice received transplants under the kidney capsule with pancreatic β-islets purified from C57BL/6 mice. Mice were not treated (control n = 4), or injected the day before the transplantation with 5 × 10⁶ CD4⁺ T cells isolated from Balb/c mice and activated for 3 weeks in the presence of rapamycin (rapamycin cells, n = 6). Graft survival was monitored by glycemia levels. A graft was considered rejected when glycemia was higher than 250 mg/dL. Kaplan-Meier survival curves were compared by the log-rank test.