Rhesus macaques have effectively fought HIV with a combination of a vaccine and an immune stimulant.
HIV is making research difficult. Since its discovery in 1981, the virus has found new ways to escape treatment. This era may be over. A team from Beth Israel Deaconess Medical Center (Boston, USA) has developed an effective approach. She publishes her conclusive results in monkeys in the journal Nature (1).
36 rhesus macaques were infected with SIV, the ape-like equivalent of HIV. These animals then received, for 6 months, the antiretroviral treatment which is usually prescribed to combat the infection. “The current drugs, while they can help you survive, do not cure HIV. They control it, ”moderates Dan Barouch, author of this work. This is because they fail to reach viral reservoirs. Lifelong treatment is therefore necessary.
“Kick and kill “
“The aim of the study was to identify a functional cure for HIV – not to eradicate the virus but to control it without having to resort to antiretrovirals,” adds Dan Barouch. Objective achieved, at least in part. The monkeys were divided into four groups: those who received two experimental vaccines, those who took an immune stimulant (TLR-7). The third group tested a combination of the two approaches. The last one served as a control.
The combination follows the ‘dislodge and kill’ strategy (kick and kill). It provides a complement to antiretrovirals. This is because the vaccine teaches the body how to get rid of the virus by eliciting a specific immune response. However, HIV has the capacity to attack the cells produced and destroy some of them. He remains sleeping in the others. These are called reservoirs, which are not reached by antiretrovirals. The immune stimulant solves this problem: it wakes up dormant copies of the virus.
The virus gives way
This diet was administered to the monkeys every two weeks for a period of 10 weeks. The antiretroviral treatment was then withdrawn. The researchers observed the evolution of the animals over a period of two years. Macaques treated with the combination exhibited a marked reaction. In terms of the number of immune cells generated and the viral locations targeted, the impact is the strongest. Not only is the viral load reduced, but the reservoirs are also effectively affected.
Result: The monkeys did not experience a rebound immediately after stopping the drugs. For a third of them, the viral load remained undetectable. “If the viral load of all the animals had been undetectable, it would have been a home run, concedes Dan Barouch. But the fact that all animals showed a reduction in viral load, and that it was undetectable in one in three cases, provides a solid first basis. It now remains to reproduce these results in humans. If three teams are in the starting blocks, the race is far from won.
(1) This study was conducted by Beth Israel Deaconess Medical Center in collaboration with the Walter Reed Institute for Military Research and two pharmaceutical companies, Janssen and Gilead Sciences.
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