HEK-BLUE assay

SZU-106 was synthesized as described above. HEK-BLUE hTLR7 cells were purchased from InvivoGen (San Diego, CA). This cell line stably expresses human TLR7 and a SEAP reporter, which can be used to detect TLR7 agonism through the activation of NF-kB signaling. The cells were maintained in selective DMEM growth medium with an additional 10 μg/ml blasticidin and 100 μg/ml Zeocin™ (Fisher Scientific, #{"type":"entrez-nucleotide","attrs":{"text":"R25001","term_id":"779889","term_text":"R25001"}}R25001, USA). After incubation with different doses of SZU-106 for 2 days, the reporter gene SEAP expression was detected using the HEKBLUE detection kit according to the 'manufacturer's instruction. The TLR7 agonist R848 was used as the positive control.