A representative flow cytometric dot plot analysis of CD4+CD25+ T cells and the corresponding gated histograms of FoxP3+ T cells in the spleen (left panels) and thymus (right panels) of the indicated mice at 21 days after transfer. (A) Irradiated SCID mice transferred with 1.5 × 104 splenocytes from naive BALB/c mice. (B) Irradiated SCID mice transferred with 1.5 × 104 splenocytes from CD61 KO mice immunized against BALB/c platelets and (C) irradiated SCID mice transferred with 1.5 × 104 splenocytes from CD61 KO mice immunized against WT BALB/c platelets and treated biweekly with 2 g/kg IVIg. Freshly isolated splenocytes and thymocytes were stained and analyzed by flow cytometry using a lymphocyte gate based on anti-CD4 green and CD25 red fluorescence in the dot plots. The histograms of FoxP3+ cells in the CD4+CD25hi+ fluorescent gate are shown.