Taking a toll: Antiviral drugs activate immune system

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.