Inhibitory activity of DR5s to the cytotoxicity of LaDR5 or TRAIL in Jurkat cells. 0.64 μg/mL LaDR5 or 0.16 μg/mL TRAIL was chosen according to the standard curve in Figure 1D to induce apoptosis of 50 % cells. A: Competing activity of DR5s against membrane DR5. The left panel displayed the OD value of LaDR5 treated sample contrasting to normal cells (control); the right panel indicated the competition of DR5s against membrane DR5 to rescue cells from apoptosis. DR5WT and its mutants DR5M1 could interfere the cytotoxicity of LaDR5 in Jurkat cells, while DR5M2 and DR5M3 couldn’t, indicating that DR5M2 or DR5M3 lacked the capacity to bind LaDR5, which was also consistent with ELISA results shown in Figure 4; B: None of DR5WT or its mutants could inhibit the cytotoxicity of TRAIL in Jurkat cells. The experimental error is the SD from three independent experiments.