• [User Manual] PathHunter® β-Arrestin Assay for GPCR Cell Lines

    PathHunter β-Arrestin cell lines are stable clonal cell lines that expedite drug discovery and development by providing robust response to over 90% of all known G-protein coupled receptor (GPCRs), with accurate pharmacology. This assay measures an essential pathway in GPCR activation, i.e. β-arrestin recruitment to activated GPCRs, enabling scientists...

    [User Manual] PathHunter® β-Arrestin Assay for GPCR Cell Lines

Assay Principle

The KILR retroviral particle is a Moloney Murine Leukemia Virus (MMLV) engineered to drive expression of the KILR reporter construct, a housekeeping gene tagged with Enhanced ProLabel® (ePL), a β-galactosidase (β-gal) reporter fragment. The KILR Retroparticles for Suspension cells contain a hybrid LTR promoter for expression of the fusion protein in difficult-to-transduce suspension cell lines, whereas the KILR Retroparticles for Adherent cells use a CMV promoter for expression of the KILR construct in most adherent cell lines. When stably transduced with the KILR Retroparticles, the target cells express the KILR reporter construct inside the cells. Death of the cells leads to rupture of the cell membrane and the KILR reporter protein is released into the medium. Addition of KILR detection reagent, containing the complementing β-gal reporter fragment, Enzyme Acceptor (EA), results in complementation of the two enzyme fragments (EA and ePL; See Figure 1). The resulting active enzyme hydrolyzes substrate to generate a chemiluminescent signal.

Applications of the KILR Cytotoxicity Assays

1. Antibody dependent cell-mediated cytotoxicity (ADCC)
2. Complement dependent cytotoxicity (CDC)
3. Antibody dependent cell phagocytosis (ADCP)
4. Cytotoxic t-cell lymphocyte mediated death (CTL)
5. Bi-specific antibody mediated T-cell redirection
6. Chimeric antigen receptor t-cell (CAR-T)
7. Adoptive T-cell therapies