WE don鈥檛 yet know why HIV spreads to women so much more readily in Africa than elsewhere, but African women desperately need protection from the virus during sex. Now a cheap and relatively safe chemical that damps down vaginal inflammation may do just that.
Ashley Haase and colleagues at the University of Minnesota in Minneapolis have discovered that a few epithelial cells on the cervix of female macaques are the first point of entry for SIV, the monkey equivalent of HIV. 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 happen to be the very cells SIV (and HIV) use to infect their new host.
Studies of , a life-threatening bacterial infection that can affect women using tampons, had already identified chemicals that can suppress vaginal inflammation, including glycerol monolaurate, a constituent of vegetable oils used widely in food and deodorants.
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When Haase鈥檚 team mixed glycerol monolaurate with vaginal lubricant, and applied it to the vaginas of five macaques, they found that the animals resisted infection even after repeated exposure to SIV. It seems the chemical blocked the immune reaction that summons the T-cells to the cervix (Nature, ).
It is not yet clear whether glycerol monolaurate would block HIV in a woman鈥檚 cervix already inflamed by other infections, or whether blocking cervical immune responses might leave her less protected from other infections. But the team argues that even if the gel 鈥� which costs less than a cent a dose 鈥� is only 60 per cent effective, it would prevent nearly a million infections a year, and might slow the heterosexual transmission of HIV in Africa.
鈥淓ven if the gel was 60 per cent effective, it would prevent nearly a million HIV infections a year鈥�
