STING agonist 4 is an amidobenzimidazole (ABZI)-based compound that functions as a STING agonist with Kd of 1.6 nM (binding of endogenous full-length STING, THP-1 cell lysates); caused dose-dependent phosphorylation of IRF3 and STING that was inhibited by the TBK1 inhibitor BX795, induced dose-dependent secretion of IFN-β with EC50 of 3.1 uM in PBMCs (18-fold more potent than cGAMP); promotes production of IFN-γ-induced protein 10 (IP-10), IL-6 and TNFα by a mechanism that is dependent on STING-mediated activation of TBK1; unlike cGAMP and DMXAA, compound 2 efficiently activates STING function while maintaining an open STING confirmation.
