Antioxidants prevent radiation-mediated increase in CD20 expression and ROS generation. (A) The kinetics of CD20 expression and (B) changes in ROS generation were measured with respect to untreated control by flow cytometry after different treatments with amifostine, radiation, or a combination of amifostine with radiation. Cells were treated with amifostine (0.1 μg/ml; 1 h) followed by irradiation (Daudi, 1.5 Gy; Raji, 2.0 Gy) and thereafter cells were washed to remove the amifostine as described under Materials and methods. Expression of CD20 and ROS was measured by flow cytometry using anti-CD20 phycoerythrin-conjugated antibody and CM-H2DCFDA, respectively. The data were analyzed using FlowJo 6.4.1 and the results are expressed as the mean fluorescence for ROS generation or CD20 expression. The statistical comparisons were done using ANOVA (*p<0.05, **p<0.01, ***p<0.001 for control vs radiation, #p<0.05, ##p<0.001 for radiation vs amifostine+radiation).