CD4⁻ cells converted from CD4⁺ T cells show distinctive cell-surface marker and cytokine expression profiles. (A) The induced CD4⁻ T cells were stained with antibodies to indicate cell-surface markers. (B) The relative expression of CD4 and CD8 genes was determined by real-time RT-PCR on different cell populations. Results shown here represent 3 independent experiments. (C) Most of the DN T cells are annexin V⁻, although most of the activated CD4⁺ T cells are annexin V⁺. The horizontal bars gate annexin V staining positive cells, and the numbers refer to the percentages of these cells. (D) CD4⁺Foxp3^-GFP− and CD4⁺Foxp3^−GFP+ T cells from Foxp3-GFP knock-in C57BL/6 mice were stimulated with mature DBA/2 DC alone or plus rIL-15 for 6 days. The DN T cells are GFP⁻ (Foxp3⁻). (E) The relative expression of indicated genes was determined by real-time RT-PCR on different cell populations. Results shown here represent 4 independent experiments. *CD4⁺CD25⁻ T DN: DN T cells converted from CD4⁺CD25⁻ T cells. **Treg DN: DN T cells converted from CD4⁺CD25⁺ Treg's.