EL-4 cells were more resistant to ionizing radiation induced cell death as compared to normal murine lymphocytes.

<p>(A) Flow cytometric profile of propidium iodide stained normal murine splenic lymphocytes cultured for 24 h post 4 Gy irradiation. Pre-G1 peak (gate RN1) represents apoptotic population. (B) Bar graph represents percent apoptotic cells. Data points represent mean±S.E.M. from nine replicates from three independent experiments. *p<0.01, as compared to irradiated lymphocytes. (C) ROS levels in normal splenic lymphocytes and EL-4 cells were estimated by staining with DCF-DA (20 µM), DHE or DHR123 (5 µM each) 30 min at 37°C followed by fluorescence emission measured at their respective wavelength. Bar graph shows relative fluorescence units indicating ROS levels, mean±S.E.M. from nine replicates from three independent experiments. *p<0.01, as compared to normal lymphocytes. (D&E) One million splenic lymphocytes stimulated with anti-CD3/anti-CD28 antibodies for 72 h in 24-well plate or EL-4 cells were exposed to ionizing radiation (4 Gy) and cultured for 24 h. Cells were stained with propidium iodide and acquired on flowcytometer. Data points represent mean±S.E.M. from nine replicates from three independent experiments. *p<0.01, as compared to activated and irradiated lymphocytes.