Promising HIV/AIDS Vaccines on the Horizon?

In an effort to make testing on HIV/AIDS drugs more successful and more productive, scientists have produced a distinctive strain of the human AIDS virus that is capable of infecting monkeys, specifically the pig-tailed macaque. This will allow these monkeys to be tested with newly created vaccines before they have to be tested on humans. This new strain infects the monkeys and multiplies in them in a similar manner that the human AIDS virus does.

Scientists were successful in creating this strain by modifying one gene in the human version of the virus. Once this scientifically engineered virus is injected into the monkeys, it reproduces almost exactly the way it does in human patients. The one difference, however, is that eventually the animal’s system is naturally able to suppress the virus so that the monkey never gets a full-blown version that causes it to get sick. Scientists have termed this strain as stHIV-1 (simian-tropic HIV-1).

Researchers and scientists that developed this new strain are hoping they can test new HIV/AIDS vaccines on these infected monkeys before they need to begin human trials. Before this, the most similar monkey version of HIV was called SIV (simian immunodeficiency virus) which resulted in symptoms in monkey that resembled those that occurred in humans. Scientists are mindful of the fact that this new strain (stHIV-1) does not match the human version perfectly, thus, vaccines tested on monkeys infected with this strain will not constitute an exact substitute for human trials. A researcher on this team, Paul Bieniasz, states, “If our research is taken further, we hope that one day perhaps in the not-too-distant future, we’ll be able to make vaccines that are intended for use in humans and the very same product will be able to be tested in animals before human trials.”

Bieniasz goes on to say, “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. 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.”

In order to create this new strain, the scientists involved in this project stated they needed to remove a gene called vif from HIV and replace it with the vif version of SIV.
This gene is responsible for fending off those monkey-produced proteins that eliminate viruses. In order to make this new strain more effective, scientists will have to modify the strain a bit more to get it to be a more perfect match to better test vaccines and drugs. One very large difference between the newly developed strain and HIV is that when a monkey is first infected, its body impersonates what happens to people when first infected with HIV; however, as the virus spreads in the monkey, its body is able to suppress the virus enough that the virus no longer has an effect on the monkey. Says Bieniasz, “The slight problem is the monkeys don’t go on to develop AIDS, they don’t get sick.”