DNTs are more sensitive to Notch inhibition than other cell populations. The effect of DAPT was assessed on different cell populations in mouse spleens at sacrifice. (A) Absolute number of cells in different lymphocyte populations (absolute cell count in spleen × % of lymphocyte subset by flow cytometry), comparing 5 treated to 7 control animals. Percentages listed on X-axis represent mean percentage reduction of cells in treated animals compared with control. Error bars represent SEM. There was a 68% decrease in the average number of total cells comparing treated to control animals. A profound decrease (81%, P = .007) was found in the DNT cell compartment. A less significant decrease was found in CD4⁺ (45%), CD8⁺ (20%), and non–T-cell (CD3⁻) (59%) lymphocytes. (B) Relative percentage of each lymphocyte population in mouse spleens comparing treated to control animals.