TLR8 is primarily expressed in monocytes, macrophages and myeloid dendritic cells (DCs) and is responsible for recognizing uridine-rich single-stranded RNA (ssRNA) from viruses and bacteria . TLR8 is a homodimer and has two conformations, active and inactive, both with experimental structures of their ectodomains available . In the active conformation, the homodimers are in closer proximity to each other compared to the inactive conformation, with the C termini distance being 30 Å in the active conformation and 53 Å in the inactive conformation.