Rapid Quantification of Bioactive Ligands in Serum and Human Plasma Using PathHunter eXpress β-Arrestin GPCR Assays

In this application note by DiscoveRx, a method is described for biomarker discovery that can detect and quantitate biomarkers as well as differentiate between biologically active and inactive fragments. The functional activity of CCL5 ligand in patient plasma samples was assessed using the PathHunter eXpress β-Arrestin CCR5 GPCR assay. The effects of diluting the culture medium as well as using plasma versus tissue culture medium, on the sensitivity of the assay were analysed. Plasma samples of 83 patients undergoing coronary artery bypass grafting were also analysed for concentration of CCL5 by ELISA and for functional activity of CCL5 via β-arrestin assays on CHO-K1 PathHunter eXpress CCR5 cells.