Normal development of lymphocytes in r1ΔT/r2n mice. (A) Flow cytometry of thymi stained with antibodies to CD4 and CD8. CD4⁻/CD8⁻ (DN) gated thymocytes were also stained with CD44 and CD25 (lower panel). (B) B220 and Thy1.2 expression on splenocytes and CD4/CD8 staining on lymph node cells. Top panels, Cre⁻; bottom panels, Cre⁺. (C) Histograms of CD69 expression in CD4⁺ and CD8⁺ single-positive thymocytes and lymph node cells as well as expression of memory markers CD44 and CD62L in CD4⁻ or CD8⁻ gated lymph node cells. Numbers represent percentages of cells in the quadrants or regions indicated. Data are representative of 3 sets of littermates.