Scientists make HIV strain that can infect monkeys

Scientists have struggled to create an AIDS vaccine.

"If you make a drug that's effective against HIV, sometimes it works against SIV and sometimes it doesn't. So that basically devalues SIV as an animal model for doing experiments involved with developing drugs," Bieniasz said.

"Now if you want to develop a vaccine, essentially what you have to do is to make a parallel vaccine for HIV and for SIV. You can test the SIV vaccine in animals and then have to make the leap of faith that the same approach would work equivalently in humans."

Writing in the journal Proceedings of the National Academy of Sciences, the scientists said in making the genetically engineered virus they removed the HIV version of a gene, known as vif, and inserted the SIV version. This gene acts to thwart proteins made by the monkey that that kill viruses.

Bieniasz said the scientists may need to make additional changes in the stHIV-1 to make it better for testing vaccines.

The genetically engineered virus infects the monkeys and during the early course of infection is a reasonably good mimic of what happens in HIV-infected people, Bieniasz said.

But after initially spreading in the monkey's body, the animal succeeds in suppressing the virus -- not completely clearing the virus but driving it to very low levels.

"The slight problem is the monkeys don't go on to develop AIDS, they don't get sick," Bieniasz said.