Assay Method Information

Assay Name:  HEK293-Blue-hTLR-7 Cells Assay
Description:  A stable HEK293-Blue-hTLR-7 cell line was purchased from InvivoGen (Cat.#: hkb-htlr7, San Diego, Calif., USA). These cells were designed for studying the stimulation of human TLR7 by monitoring the activation of NF-κB. A SEAP (secreted embryonic alkaline phosphatase) reporter gene was placed under the control of the IFN-3 minimal promoter fused to five NF-κB and AP-1-binding sites. The SEAP was induced by activating NF-κB and AP-1 via stimulating HEK-Blue hTLR7 cells with TLR7 ligands. Therefore the reporter expression was regulated by the NF-κB promoter upon stimulation of human TLR7. The cell culture supernatant SEAP reporter activity was determined using QUANTI-Blue kit (Cat.#: rep-qb 1, Invivogen, San Diego, Ca, USA) at a wavelength of 640 nm, a detection medium that turns purple to blue in the presence of alkaline phosphatase.HEK293-Blue-hTLR7 cells were incubated at a density of 250,000 450,000 cells/mL in a volume of 180 μL in a 96-well plate in Dulbecco's Modified Eagle's medium (DMEM) containing 4.5 g/l glucose, 50 U/ml penicillin, 50 mg/ml streptomycin, 100 mg/ml Normocin, 2 mM L-glutamine, 10% (v/v) heat-inactivated fetal bovine serum for 24 h. Then the HEK293-Blue-hTLR-7 cells were incubated with addition of 20 μL test compound in a serial dilution in the presence of final DMSO at 1% and perform incubation under 37° C. in a CO2 incubator for 20 hours. Then 20 μL of the supernatant from each well was incubated with 180 μL Quanti-blue substrate solution at 37° C. for 1-3 hours and the absorbance was read at 620 655 nm using a spectrophotometer. The signalling pathway that TLR7 activation leads to downstream NF-κB activation has been widely accepted, and therefore similar reporter assay was also widely used for evaluating TLR7 agonist (Tsuneyasu Kaisho and Takashi Tanaka, Trends in Immunology, Volume 29, Issue 7, July 2008, Pages 329.sci; Hiroaki Hemmi et al, Nature Immunology 3, 196-200 (2002).
Affinity data for this assay
 

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