Toll-like receptor 9, Toll-like receptor 7, Toll-like receptor 8 (TLR9, TLR7, TLR8)

Toll-like receptor 7, Toll-like receptor 8, and Toll-like receptor 9 are intracellular pattern recognition receptors (PRRs) belonging to the Toll-like receptor family. They are localized primarily in endosomal compartments of immune cells such as dendritic cells, B cells, and monocytes, where they detect viral and bacterial nucleic acids. Upon ligand binding—single-stranded RNA for TLR7 and TLR8, and unmethylated CpG DNA for TLR9—they initiate robust signaling cascades involving MyD88 and other adaptor proteins, leading to the production of type I interferons and pro-inflammatory cytokines. These receptors play crucial roles in pathogen recognition, antiviral defense, and regulation of autoimmunity. Aberrant activation or regulation of TLR7/8/9 is implicated in autoimmune diseases like systemic lupus erythematosus and their ligands/antagonists are under investigation as immunotherapies for cancer and inflammatory disorders[3][4][2][6][8][9][5][7][1].

Other names

TLR9 (Toll/interleukin-1 receptor 9)TLR7 (Toll/interleukin-1 receptor 7)TLR8 (Toll/interleukin-1 receptor 8)endosomal TLRs

Agonists: Activate TLR signaling, enhance immune response via cytokine and interferon induction, stimulate antiviral and anticancer immunity. Antagonists: Block TLR-mediated signaling, reducing inflammatory and autoimmune activity.