Effect of mAb TM-311 on HKa-induced endothelial cell apoptosis assessed by endonucleolytic cleavage of DNA. Endothelial cell DNA was isolated from cells cultured for 12 h in the presence of mAb TM-311 alone (lane 1), 20 nM HKa (lane 2), 20 nM HKa + 60 nM TM-311 (lane 3), 50 nM HKa D5 (lane 4), 50 nM HKa D5 + 150 nM mAb TM-311 (lane 5), 2 μM 2-methoxyestradiol (lane 6), or 2 μM 2-methoxyestradiol + 6 μM mAb TM-311 (lane 7) and analyzed as described in Materials and Methods. M, markers.