The PathHunter U2OS IL1RL1/IL1RAP Bioassay Kit provides an easy-to-use cell based assay to measure drug potency and detect neutralizing antibodies. This bioassay asseses ligand (e.g. GM-CSF) based on activation of IL1RL1/IL1RAP Cytokine activity via detection of Dimerization. The included cell line overexpresses ProLink-tagged IL1RL1/IL1RAP and EA-tagged . Activation of IL1RL1/IL1RAP stimulates the recruitment of and produces EFC signal. Bioassay kits are a convenient, ready-to-use format which contains all materials needed to run the assay, including single-use vials of cryopreserved cells, cell plating media, control agonist, detection reagent, and assay plates.