TLR7

TLR7 is an endosomal pattern-recognition receptor that detects single-stranded RNA (ssRNA) and supports antiviral innate immunity^[1]. Mechanistically, TLR7 activation engages IRF and NF-κB programs, producing type I interferon-related and inflammatory responses that vary by immune cell type^[1]. In inflammatory contexts, NF-κB can also prime non-native TLR7-expressing cells to respond to TLR7 agonists with pro-inflammatory signaling^[2]. Disease models link TLR7/TLR8 activation to lupus-related autoimmunity, and TLR7-driven signatures appear in human cells and lupus mouse models^[1]. Compared with TLR8, TLR7 shows distinct ligand specificity, cellular expression, and pathway bias, supporting nonredundant functions among RNA-sensing endosomal isoforms^[1][3]. In human monocytes during RNA virus infection, TLR7 and TLR8 activate distinct signaling pathways and generate different cytokine-related phenotypes^[3]. For experimental applications, TLR7-selective agonists such as CL-087 help separate direct TLR7 responses from TLR8-driven inflammatory programs in human immune cells^[1]. Small-molecule modulation remains useful for isoform-dissection studies because selective TLR8 antagonists demonstrate that closely related endosomal TLRs can be pharmacologically separated^[4].