Human rIL-2 transiently increases peripheral blood CD4+ and CD8+ Tregs in a dose-dependent manner . (A) Gating strategy for the identification of Treg cells. Cells were first gated on side and forward scatter parameters (gate R1) and further gated on CD4+ T cells (gate R2) to analyze CD25 and FoxP3 expression. CD4+FoxP3+CD25high or CD8+FoxP3+CD25high (R3) were then analyzed for CD127 expression. CD4+FoxP3+CD25highCD127low or CD8+FoxP3+CD25highCD127low were identified as CD4 or CD8 Tregs respectively. (B) Percentages and counts of peripheral blood CD4+CD25high and CD8+CD25 high cells in IL-2-treated macaques (low dose, #056212, #056216 – high dose, #056230, #056238) at days 0, 7 and 45 after IL-2 treatment. (C) Percentages and counts of CD4 or CD8 Tregs in IL-2-treated macaques (low dose #056212, #056216 – high dose #056230, #056238) at day 0, 7 and 45 after IL-2 treatment.