* Gel prevents AIDS-like infection in monkeys
* Ingredient used safely in food and cosmetics
* Costs pennies a dose
WASHINGTON, March 4 (Reuters) - A cheap ingredient used in ice cream, cosmetics and found in breast milk helps protect monkeys against infection with a virus similar to AIDS and might work to protect women against the virus, researchers reported on Wednesday.
The compound, called glycerol monolaurate, or GML, appears to stop inflammation and helps keep away the cells the AIDS virus usually infects, the researchers said.
While it does not provide 100 percent protection, it might greatly reduce a woman's risk of being infected, and she could use it privately and without hurting her chances of pregnancy, the researchers reported in the journal Nature.
And it costs pennies a dose, Ashley Haase and Pat Schlievert of the University of Minnesota reported.
"For years, people have used the compound as an emulsifying agent in a variety of foods ... it is in breast milk," Schlievert told reporters in a telephone briefing.
GML is being considered as an additive to tampons because it interferes with bacteria, particularly those that can cause a potentially fatal infection called toxic shock syndrome.
If it can be shown to work safely in women, GML might provide the first easy route to a microbicide -- a gel or a cream that women could use vaginally to protect themselves from infection with the human immunodeficiency virus, or HIV, which causes AIDS.
HIV infects 33 million people globally and has killed 25 million. It is transmitted sexually, in blood and breast milk. In Africa, it is most commonly passed during heterosexual contact.
AIDS experts say many victims are married women whose husbands will not use condoms and who are often trying to have children. They need a safe and private way to protect themselves.
A microbicide (pronounced my-CROW-buh-side) might also protect men who have sex with men.
Haase and Schlievert's team tested GML, carried in KY jelly, in macaque monkeys. They put the gel into the vaginas of the monkeys and then applied SIV, a monkey version of HIV.
Four out of five monkeys never became infected and tests showed GML affected the immune response.
HIV is particularly hard to fight because it infects the very immune cells the body uses to attack a virus. When HIV infects an area such as the vagina, the CD4 T-cells rush to defend against it. The body sends out signaling chemicals called cytokines to call in more T-cells.
HIV can then infect them all and spread through the body.
GML appears to stop the cytokine call for help and stops so many T-cells from rushing to the area, Haase and Schlievert said. This in turn reduces the opportunity for HIV to take hold.
"This result represents a highly encouraging new lead in the search for an effective microbicide to prevent HIV transmission that meets the criteria of safety, affordability and efficacy," they wrote.
Even if it was only 60 percent effective, such a gel could prevent 2.5 million HIV cases over three years, they said.
They said they plan to study their gel in more monkeys for longer periods of time to ensure the gel is not simply delaying infection rather than preventing it. (Editing by Will Dunham)
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