We’ve been talking about new HIV therapies and prevention methods a lot lately, but it’s only because there are so many promising developments being made on the race to a cure. Currently, a new preventative method is being researched and its source may surprise you.
It shouldn’t be news that HIV is spread sexually. The human immunodeficiency virus, which is spread from person-to-person via the bodily fluids of the infected partner, can be transmitted through blood, semen, or vaginal secretions. Unprotected sex and intravenous drug use are the top two transmission methods of HIV.
During sexual transmission, semen is the principal carrier because it is rich in protein, which is why receptive vaginal and anal sex carry a much higher risk of contracting HIV than being the insertive participant. Semen is the primary carrier of HIV because it contain polymers that help the virus attach itself to the membranes that surround human cells. These polymers, called amyloid fibrils, make the rate of transmission up to 10,000 times more likely to occur.
New research out of Perelman School of Medicine at the University of Pennsylvania suggests that because of the link between amyloid fibrils and HIV transmission, reducing the number of polymers in the semen would reduce the transmission rate of the virus.
“Each strategy diminished the ability of amyloid to promote HIV infection, so this approach has potential as a therapeutic,” James Shorter, Ph.D., said.
Two new methods of fighting the virus are being developed based on attacking the proteins in semen during the initial infection phase. He and his colleagues outlined how this could be accomplished in two studies. The first study, published in 2012, outlined how to use the protein-remodeling factor Hsp104, a yeast heat shock protein, to work with an enzyme and break down semen’s amyloid fibrils. They also used Hsp104 to attack, or “shock,” the amyloid fibrils, which resulted in a remodel of the polymers into non-amyloid forms.
The second study, published in 2015, explains a tweezer-shaped molecule, called CLR01, that both interferes with the ability of the amyloid fibrils to aid in the transmission of HIV and attacks the virus itself, as well as other enveloped viruses like hepatitis C, the herpes simplex virus, and possibly Ebola. The CLR01 molecule can interfere with the formation of amyloid fibrils and deconstruct fibrils that have already formed. It also disrupts the membranes that enclose viruses, which prevents HIV from interacting with the amyloid fibrils in the first place, lessening the chances of transmission. When CLR01 was present, HIV-infected semen was 100 times less likely to infect human cells.
“Remarkably, CLR01 does not affect cell membranes, which suggests it could be safely incorporated into a vaginal or anal gel to prevent HIV infection – without the risk of side effects,” Shorter said.
Use of CLR01 has proven safe in zebrafish and mice, so the next step is to test the efficacy of the molecule in non-human primates.
This is an exciting discovery that could prove extremely valuable in the fight against HIV and AIDS. Creating a method to reduce the likelihood of contracting HIV that can be used as easily as a condom or lubricant would make sex safer for a wide swath of the population. The incorporation of amyloid fibril-destroying molecules into a vaginal or anal gel, as mentioned by Dr. Shorter, would revolutionize HIV prevention for sexually active people of every sexual orientation.