A CD25+4+ T cell population is generated in T/R+ but not in T/R− mice. (A) Expression of CD25 on CD4+ LN cells and CD4+8− thymocytes from 6- to 7-week-old T/R+, T/R−, and R+ litters, determined by flow cytometry. The number in the upper right quadrant of each profile refers to the mean (±SD.) percentage of CD4+ cells expressing CD25 (n = 3 in each group). (B) Expression of Tg-TCR on CD25+ and CD25−4+ LN cells, determined by flow cytometry with anti-clonotype mAb, 3H12. (C) Representation of 3H12− cells in each lymphoid organ. Mean ± SD (n = 3).