HIV may soon fight HIV

Vaccines against many viruses, including flu, are made from deactivated versions of those viruses, but such an approach was previously dismissed as too risky in the case of HIV. Now, scientists are resurrecting the controversial approach.

VIRxSYS of Gaithersburg, Maryland, is planning to inject people with an HIV vaccine made of the deadly virus itself, albeit a deactivated version.

Their plan follows successful tests of a similar vaccine against SIV - also known as simian HIV - in monkeys.

"We said 'let's use HIV against itself', and that's what we're doing," New Scientist quoted Gary McGarrity, VIRxSYS's vice president of scientific and clinical affairs, as saying.

VIRxSYS researchers described how they vaccinated monkeys, and then six months later injected them with SIV.

Within weeks of receiving the injection of SIV, concentrations of the virus had fallen by at least 95 per cent in those treated.

After a year, when the trial ended, these concentrations remained low, whereas untreated monkeys became progressively sicker as their immune systems were depleted by the virus.

What's more, in vaccinated animals, concentrations of CD4+ cells - the immune cells that both HIV and SIV attack and kill - remained the same, suggesting their immune systems were able to withstand SIV infection.

The findings have been presented at the 2010 annual Conference on Retroviruses and Opportunistic Infections in San Francisco.