GeneBLAzer™ HTR2B-NFAT-bla CHO-K1 cells contain the human 5-hydroxytryptamine (serotonin) receptor 2B (HTR2B), (Accession No. NM_000867) stably integrated into the CellSensor™ NFAT-bla CHO-K1 cell line. CellSensor™ NFAT-bla CHO-K1 cells contain a beta-lactamase reporter gene under control of the NFAT Response Element. The GeneBLAzer™ HTR2B-NFAT-bla CHO-K1 cells are functionally validated for Z'-factor and EC50 concentrations of 5-HT (Figure 1). In addition, GeneBLAzer™ HTR2B-NFAT-bla CHO-K1 cells have been tested for assay performance under variable conditions.