Researchers identify compound that could prevent HIV transmission
Researchers at the University of Minnesota have identified a compound that, applied vaginally, can prevent transmission of the primate version of HIV, called SIV.
While it’s not a cure—and the compound still must go through human clinical trials before it can be used to prevent HIV—the research is a huge step toward preventing the spread of the devastating disease.
HIV affects 33 million people worldwide.
Safe, existing compound
The FDA recognizes this naturally occurring compound as safe. It is widely used as an antimicrobial and anti-inflammatory agent in food and cosmetics.
“After 25 years, an effective vaccine for HIV is still on the distant horizon, so not only vaccines, but all research into ways to prevent the continued spread of this lethal virus remain critically important,” Haase said. If GML as a topical microbicide could be used to prevent HIV "it could contribute to saving millions of lives.”
How the virus spreads
After sexual exposure to SIV, the researchers found that the body’s natural defense system is activated, rushing immune cells (T-cells) to the scene of the infection. The virus uses these T-cells as fuel to expand infection locally and spread it throughout the body.
“So even though it sounds counter-intuitive, halting the body’s natural defense system might actually prevent transmission and rapid spread of the infection,” Haase said. “That’s where GML comes in.”
How the gel works
They examined GML because in 1992 Schlievert began using it to combat toxic shock syndrome—a potentially lethal bacterial infection. In recent years, research has shown GML is active against a variety of toxins and microbes and inhibits cytokines and chemokines, small molecules that play key roles in triggering the body’s defense system.
Since these were the processes they wanted to inhibit, it made sense to see if GML might prevent transmission, Haase said.
Before testing their theory, the researchers tested GML’s safety. The researchers then gave large doses of SIV to 5 GML-treated and 5 control animals.
The researchers monitored the animals for evidence of transmission for 2 weeks—infected animals would typically have hundreds of millions of viruses circulating in the blood stream. If there was no evidence of infection, the treatments and viral challenges were repeated.
4 of 5 in the control group contracted SIV, while none of the 5 in the GML-treated group showed any evidence of infection.
Making the link to humans
Researchers believe GML has potential to be an effective way to prevent vaginal transmission of HIV in humans, which is how a majority of new cases are acquired around the globe. Of the more than 33 million people infected with HIV or diagnosed with AIDS, 67% live in the sub-Saharan region of Africa, and women represent close to 60% of new infections in this epicenter of the pandemic.
But Haase cautions that there is still a lot of work to be done before planning clinical trials in humans. This includes:
- Additional testing in animals
- Developing a dosing and a delivery method that will make it more likely that women will use GML
- Longer term follow-up studies into hidden infections that weren’t apparent in the acute stage of infection, but may show up months later.