Antibodies against HIV infection
The combination of HIV antibodies has passed the first clinical trial
A prototype antibody–based HIV drug has passed its first clinical trial - it successfully suppressed infection in the body of volunteers for four months after giving up antiretroviral drugs. The results of the experiments were presented in the journal Nature (Mendoza et al., Combination therapy with anti-HIV-1 antibodies maintains viral suppression).
"Safe and reliable antibody-based HIV therapy will open up a lot of new opportunities for carriers of this infection. We have taken a big step towards realizing this dream by showing that a combination of certain antibodies can suppress infection for a long time without developing "invulnerability" by the virus," said Antony Fauci, head of the US National Institute of Allergy and Infectious Diseases in Bethesda.
The Achilles heel of HIV
Three years ago, Marina Caskey and her colleagues from Rockefeller University in In New York (USA), an extremely unusual antibody 3BNC117 was discovered, capable of suppressing the reproduction of several varieties of the human immunodeficiency virus at once and "tagging" them for destruction by the immune system.
The secret of 3BNC117's action lies in the fact that this antibody attacks a key part of the virus – an outgrowth on its shell, which clings to the "tails" on the surface of immune cells and helps the "warhead" of the virus to penetrate them.
It was isolated by American scientists from the body of an HIV-infected person whose body resisted infection unusually strongly and fought well with new strains of the virus. Two years ago, scientists conducted the first clinical trials on volunteers, which showed that this antibody can be used for long-term suppression of infection.
The success of these experiments led Kaski and her team to the idea that 3BNC117 and another broad–spectrum antibody – 10-1074 - can be used to acquire almost complete immunity to HIV. They successfully tested this idea on several macaques, infecting them with a monkey version of the immunodeficiency virus and immediately treating them with a mixture of antibodies.
Emboldened by such successes, scientists began conducting the first clinical trials with the participation of eight volunteers who contracted HIV about five years ago and regularly take antiretroviral drugs. They agreed to temporarily abandon these medications and switch to periodic injections of antibodies.
Antibody Alliance
In parallel, they conducted similar experiments involving seven volunteers who had recently become infected with HIV and had not yet started taking antiretroviral drugs. In both cases, biologists regularly took blood samples from their wards and monitored how the concentration of viral particles in their blood changed. If their number began to grow, scientists stopped experiments and transferred volunteers to classical treatment.
Such incidents, as Kaski and her colleagues note, were exceptions – in fact, all volunteers from both the first and second groups successfully resisted the effects of HIV throughout the 20 weeks of the experiment. Only 3 out of 15 participants in clinical trials were forced to leave them due to the presence of viruses in their blood that resisted the action of antibodies.
In all other cases, the antibodies not only suppressed the infection, but also contributed to a decrease in the level of genetic diversity among viruses "entrenched" in various tissues of the volunteers' body. This, as biologists note, was a very good sign indicating that the virus did not begin to acquire invulnerability to their action even after four months of "war" with antibodies.
In the near future, scientists plan to conduct more large-scale experiments with the participation of a larger number of volunteers. These experiments, which will last up to 40 weeks, will help them understand how often patients' blood contains "unsuccessful" HIV strains, initially insensitive to the action of 3BNC117 and 10-1074, and how they can be suppressed.
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