 performed using either the initial T~reg~ purified from F0 DEREG C00BL/0×BALB/c mice or those that reappear in these mice after depletion. Initial T~reg~ or "new" T~reg~ were incubated with different amounts of spleen cells from OT-0 T cell receptor transgenic mice, which were subsequently stimulated with SIINFEKL-peptide. A