Frequencies of NK cells and EGFP+ cells in spleen by flow cytometry. Splenocytes were isolated from wild-type C57BL/6 mice (+/+) and heterozygous B-Ncr1 EGFP-DTR-luciferase mice (Mut/+) (n=3, 8-9-week-old) injected with PBS or DT (50 ng per g body weight) for four consecutive days. Flow cytometry analysis of the splenocytes was performed to assess the frequencies of EGFP+ cells and NK cells in total CD45+ cells. The signal for NK cells(A) and EGFP+ cells(B) were decreased in heterozygous mice injected with DT. C. Percentages of NK cells and EGFP+ cells in total CD45+ populations. The frequencies of NK cells and EGFP+ cells were decreased in heterozygous mice after DT injection.