Investigators in Japan have now found a major clue to the workings of some of the most promising antiviral medicines under development. These compounds include resiquimod, which scientists are testing against genital herpes.
The new research shows that these drugs, known as imidazoquinolines, appear to activate toll-like receptor 7 (TLR7), a protein on immune cells. Mice genetically engineered to lack TLR7 didnt have the strong, antiviral immune response to imidazoquinolines that normal mice do. When given the drugs, the mutant mice didnt produce the typical inflammatory chemicals, and their immune cells didnt proliferate and mature, Shizuo Akira of Osaka University in Japan and his colleagues report in the February Nature Immunology.