In vivo treatment with anti-CD3 mAb and resistance against apoptosis of PS KO thymocytes. Control (A, top panels; C, left panel) or PS KO thymocytes (A, bottom panels; C, right panel) were obtained 40 hours after intraperitoneal injection of PBS or 50 μg/mouse anti-CD3 mAb. Total thymocyte numbers were counted and cell numbers for DN, DP, SP4, or SP8 cells estimated by percentages of FACS analysis with anti-CD4 and anti-CD8 fluorescent mAb (B). The γ-irradiation dose was 5Gy. *P < .05. Representative of 5 animals. (A,C) Value in each quadrant represents the percentage of each cell population inside the thymus.