Identification of High-Potency Human TLR8 and Dual TLR7/TLR8 Agonists in Pyrimidine-2,4-diamines
作者:Mallesh Beesu、Alex C. D. Salyer、Michael J. H. Brush、Kathryn L. Trautman、Justin K. Hill、Sunil A. David
DOI:10.1021/acs.jmedchem.6b01860
日期:2017.3.9
The induction of toll-like receptor 7 (TLR7)-dependent type I interferons (IFN-alpha/beta) from plasmacytoid dendritic cells as well as the production of TLR8-dependent type II interferon (IFN-y), TNF-alpha, and IL-12 in myeloid dendritic cells are of importance in generating T helper-1 biased adaptive immune responses. In an effort to identify novel dual TLR7/TLR8-active compounds, we undertook structure activity relationship studies in pyrimidine 2,4-diamines, focusing on substituents at CS. Several analogues substituted with aminopropyl appendages at CS displayed dominant TLR8-agonistic activity. N4-Butyl-6-methyl-S-(3morpholinopropyl)pyrimidine-2,4-diamine was found to be a very potent dual TLR7/TLR8 agonist. Employing novel cytokine reporter cell assays, we verified that potency at TLR7 correlates with IFN-alpha/beta production in human blood, whereas IFN-y and TNF-a induction is largely TLR8dependent. Dual TLR7/TLR8 agonists markedly upregulate CD80 expression in multiple dendritic cell subsets, providing insight into the immunological basis for the superior adjuvantic properties of such innate immune stimuli.