CASE SHARING

In the field of new drug screening, cisbio biostays' patented technology htrf (homogeneous time-resolved fluorescence) is widely used in major pharmaceutical enterprises, drug research institutes and new drug screening centers around the world. Htrf, in short, is a wash free ELISA that combines fluorescence resonance energy transfer (FRET) and time-resolved fluorescence (TRF, Time-resolved floorescence) only needs three steps: adding liquid, incubation and reading board, which avoids the complicated and variable washing steps. It is not only easy to operate, but also more stable and reliable.

In recent years, PD-1 / PD-L1 immunosuppressive checkpoint inhibitor, as a new type of cancer immunotherapy, has achieved amazing results in a variety of cancer treatment. The case we selected is to use htrf technology to screen PD-1 / PD-L1 inhibitors. The experimental principle is shown in Figure 1. PD-L1 and PD1 fused tag1 and tag2 respectively, which were recognized by anti-tag1 and anti-tag2 respectively. Because of the donor fluorescent dye EU and acceptor fluorescent dye xl665 labeled with htrf on the antibody, when PD-L1 and PD1 are close and combined, the fluorescence resonance excited by EU is transferred to xl665, which makes xl665 emit fluorescence, and thus detected.

When PD-1 / PD-L1 inhibitors exist, they will block the binding of tag1-pd-l1 protein to tag2-pd-1, thus affecting the fluorescence signal intensity of xl665.