HJ901 selectively inhibits TLR7- and TLR9-mediated cell proliferation in HEK-Blue-hTLR7, HEK-Blue-hTLR9, or PBMCs cells. (A,B) HEK-Blue-hTLR7 or HEK-Blue-hTLR9 cells were cultured with 10 μM IMQ or 1 μM CpG 685 (CpG) in the presence or absence of different concentrations of HJ901 (0.004, 0.002, 0.1, 0.5, or 2.5 μM) for 24 h. (C,D) HEK-Blue-hTLR7 or HEK-Blue-hTLR9 cells were cultured with HJ901 in the presence or absence of different concentrations of IMQ (10, 30, 90, or 180 μM) or CpG (1, 3, 9, or 27 μM) for 24 h. (E,F) HEK-Blue-hTLR7 or HEK-Blue-hTLR9 cells were incubated with HJ901 for 0, 2, 4, 6, or 12 h and then treated with or without 10 μM IMQ or 1 μM CpG HJ901 for 24 h. (G,H) HEK-Blue-hTLR7 or HEK-Blue-hTLR9 cells were incubated with 10 μM IMQ or 1 μM CpG for 0, 2, 4, 6, or 12 h and then treated with or without HJ901 for 24 h, and the SEAP activity was determined. (I) Human PBMCs incorporated CFSE cultured with Poly (I: C), LPS, IMQ, or CpG in control ODN, and HJ901 cells for 5 days of treatment. (J) Human PBMCs incorporated CFSE cultured with IMQ or CpG in the presence or absence of different HJ901 concentrations for 5 days. Proliferation of CD19+ B cells was determined by CFSE dilution, which was assessed by flow cytometry. Quantification of three experiments is shown in the right panel. Similar results were obtained from three independent experiments. All data are presented as the means ± SEM (n = 5 in each group). ##p < 0.01 vs. the untreated group or HJ901 group; *p < 0.05 and **p < 0.01 vs. the IMQ or CpG group.