Protein TRAIL (TNF-Related Apoptosis-Inducing Ligand) is a cytokine that belongs to the tumor necrosis factor (TNF) ligand family. TRAIL induces apoptosis in transformed and tumor cells. This protein binds to several members of TNF receptor superfamily including TNFRSF10B/TRAILR2. Thus a binding ELISA assay was conducted to detect the interaction of TRAIL and TNFRSF10B. Briefly, recombinant human TRAIL were diluted serially in PBS, with 0.01%BSA (pH 7.4). Duplicate samples of 100uL were then transferred to TNFRSF10B-coated microtiter wells and incubated for 2h at 37°C. Wells were washed with PBST and incubated for 1h with anti-TRAIL pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody, wells were aspirated and washed 3 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37°C. Finally, add 50μL stop solution to the wells and read at 450nm immediately. The binding activity of TRAIL and TNFRSF10B was shown in Figure 1, and this effect was in a dose dependent manner.

Tumor Necrosis Factor Related Apoptosis Inducing Ligand (TRAIL) is a recently identified member of the TNF gene superfamily. TRAIL is widely expressed in a variety of human tissues, most predominantly in lung, spleen and prostat. As its name suggests, TRAIL was primarily of particular interest for its ability to selectively induce apoptosis in tumour cells?in vitro?and?in vivo, while apparently exhibiting minimal off-target effects. In order to test the effect of human recombinant TRAIL protein on cell apoptosis, 2x104 A549 cells were seeded into quintuplicate wells of 96-well plates and allowed to attach, replaced with various concentrations of recombinant human TRAIL. After incubated for 72 hours, the 96-well plates were read at OD450 nm. The result was shown in Figure1. It was obvious that rmTRAIL significantly decreased cell viability of A549 cells. The ED50 of recombinant human TRAIL is 0.84 μg/mL.