HIV, the virus that causes AIDS in humans, cannot infect rhesus monkeys even though they are biologically similar to us. Studies have shown that the animals have an innate resistance to the virus—and now Harvard immunologist Joseph Sodroski thinks he may have isolated this anti-AIDS mechanism.
Sodroski believes the key is TRIM5-alpha, a free-floating blood protein that prevents HIV from replicating. Both humans and monkeys make TRIM5, but his research shows that only the monkey version of the protein effectively stops the virus. The big question is why. “We know that TRIM5 binds specifically with the inner coat of the virus, but we’re still uncertain about what happens next,” Sodroski says. Possibly the protein prevents the virus from exposing and activating its genetic material after it has entered the host cell.
Even without understanding exactly how TRIM5 works, Sodroski’s research could jump-start the search for an HIV vaccine. Drugs designed to mimic the action of the powerful monkey TRIM5 could help block new infections. Farther ahead, gene therapy might allow people to start producing the powerful anti-AIDS protein themselves. “Researchers have long suspected that other primates were the source of the HIV epidemic,” Sodroski says. “It would be ironic if they also showed us how to end it.”