Cell experiment:

Fresh human peripheral blood mononuclear cells (hPBMC) are used. Aliquots of PBMCs (105 cells in 100 μL/well) are stimulated for 12 h with graded concentrations of test compounds (e.g., TLR7/8 agonist 1; 0.1, 1, 10, and 100 μg/mL). Supernatants are isolated by centrifugation and are assayed in duplicates using analyte-specific multiplexed cytokine/chemokine bead array assays[2].

TLR7/8 agonist 1 dihydrochloride is a toll-like receptor (TLR7)/TLR8 dual-agonistic imidazoquinoline.

TLR7/8 agonist 1 (Compound 5d) shows prominent immunostimulatory activities. TLR7/8 agonist 1 serves as a convenient precursor for the covalent attachment of fluorophores without significant loss of activity.TLR7/8 agonist 1 retains TLR7-agonistic activity with an EC50 of 20 nM. TLR7/8 agonist 1 is covalently coupled directly to commercially-available fluorescein isothiocyanate and rhodamine B isothiocyanate[1]. TLR7/8 agonist 1 (Compound 1) shows substantially different agonistic potencies in human TLR7 (50 nM) and TLR8 (55 nM) primary screens[2].

[1]. Shukla NM, et al. Syntheses of fluorescent imidazoquinoline conjugates as probes of Toll-like receptor 7. Bioorg Med Chem Lett. 2010 Nov 15;20(22):6384-6. [2]. Beesu M, et al. Structure-Based Design of Human TLR8-Specific Agonists with Augmented Potency and Adjuvanticity. J Med Chem. 2015 Oct 8;58(19):7833-49.