Molecule that targets HIV in semen to prevent infection

A tweezer shaped molecule that targets the human immunodeficiency virus (HIV) in semen can help prevent HIV infection and other sexually transmitted viral diseases, new research has found. The researchers believe that the compound could be incorporated into a vaginal or anal gel to prevent HIV infection - without the risk of side effects.

Semen, the male reproductive fluid that contains deposits of protein fragments called amyloid fibrils is the main vector for sexual HIV transmission. The researchers found that the ‘molecular tweezer’ called CLR01, not only destroys HIV particles but also blocks the infection-promoting activity of semen amyloids.

"We think that CLR01 could be more effective than other microbicides that are in development because of its dual action, its safety in terms of side effects and its potential broad application," said James Shorter, professor at University of Pennsylvania School of Medicine in the US.

"The tweezer has been tested and is safe in zebrafish and mice. The next step could be to assess safety and efficacy in non-human primates," Professor Jan Munch from University of Ulm in Germany pointed out. Semen contains proteins that assemble into amyloid fibrils, which can enhance HIV infectivity by up to 10,000 times.

The antiviral activity of CLR01 is based on the way it selectively interacts with and destroys the viral membrane. The way CLR01 operates means that it is also effective against many other sexually transmitted viruses, including Hepatitis C and viruses in the herpes family.

It may also be effective against many other ‘enveloped’ viruses including flu and Ebola, the study said. The use of other preventive treatments has been undermined in some countries by the stigma associated with HIV.

As CLR01 is effective against many viruses besides HIV, it could be more widely acceptable as a general protective agent in communities struggling with HIV stigma, suggested the study detailed in the journal eLife.