Scientists have created a strain of HIV that is able to infect and multiply in monkeys, leading to the possibility that researchers would be able to test HIV/AIDS drugs and vaccines in monkeys before testing them in humans, according to a study published in the journal Proceedings of the National Academy of Sciences, Reuters UK reports.
The strain of HIV -- called simian-tropic HIV-1, or stHIV-1 -- was developed by altering a single gene in the human version of the virus to allow it to infect a pig-tailed macaque, according to researchers. Once injected into the monkey, the stHIV-1 reproduced almost as much as it does in humans; however, the animal ultimately suppressed the virus and stayed healthy. Paul Bieniasz, a researcher on the team from New York's Rockefeller University, said, "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."
According to Reuters UK, stHIV-1 was created by removing the HIV version of a gene -- called a vif -- and inserting it into the simian immunodeficiency virus. The gene then acts to prevent proteins made by the monkey that kill viruses. The genetically engineered virus infected the monkeys and is a decently good copy of what occurs in HIV-positive people during the early stages of infection, Bieniasz said. He said that there is a "slight problem" that the monkeys "don't go on to develop AIDS, they don't get sick." The monkey succeeded in suppressing the virus after it initially spreads through its body, driving the virus to very low levels but not completely clearing it, Reuters UK reports.
According to Reuters UK, SIV -- simian immunodeficiency virus, which causes something similar to AIDS in certain types of monkeys -- is "not a perfect substitute for testing drugs and vaccines against HIV." Bieniasz said that a drug that is effective in treating HIV will sometimes work against SIV but sometimes will not. That "basically devalues SIV as an animal model for doing experiments involved with developing drugs," he said, adding, "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" (Dunham, Reuters UK, 3/3).