Damping vaginal inflammation may help prevent HIV.

Preventing vaginal inflammation may prevent women from becoming infected with HIV, if studies on female macaques can be extrapolated to humans. Ashley Haase and colleagues from the University of Minnesota have found that a few epithelial cells on the cervix of femal macaques are the first point of entry for simian immunodeficiency virus (SIV). Nearby immune cells respond by emitting molecules that trigger inflammation and summon T-cells to the cervix. These would normally destroy invaders, but T- cells are the cells that SIV (and HIV) use to infect their host.

Studies of toxic shock syndrome have already identified chemicals that can suppress vaginal inflammation, including glycerol monolaurate, a constituent of vegetable oils. When Haase's team mixed glycerol monolaurate with vaginal lubricant and applied it to the vaginas of 5 macaques, they found that the animals resisted infection, even after repeated exposure to SIV. The chemical appeared to block the immune reaction that summons the T-cells to the cervix.

It is not yet clear whether glycerol monolaurate would block HIV in a woman's cervix already inflamed by other infections, or whether blocking cervical immune responses might leave her less protected against other infections. However, the team argues that even if the gel--which costs less than $0.1 per dose is--only 60% effective, it would prevent nearly a million infections a year and might slow the heterosexual transmission of HIV in Africa.

Li Q, et al. Nature 2009: doi: 10.1038/nature07831.