HIV was kicked out of the trenches
Scientists for the first time cleared the body of monkeys of "sleeping" HIV
The combination of two antiviral drugs helped the monkeys to get rid of the immunodeficiency virus, "entrenched" in their immune cells, and protected them from the return of infection. Their findings were presented in the journal Nature (Antibody and TLR7 agonist delay viral rebound in SHIV-infected monkeys).
"The main question now is whether the drugs GS-9620 and PGT121, or other immune stimulants and antibodies, can cause a similar reaction in the human body. Similar clinical trials will be conducted soon, and we are all looking forward to their results," Sharon Lewin, a virologist from the University of Melbourne (Australia), comments on the discovery.
Trench warfare
Today, HIV patients can live for decades thanks to the use of antiretroviral drugs – substances that suppress various stages of virus replication in the cells of the body. Since they often have strong side effects, doctors are often forced to stop taking them for several weeks.
When they stop taking them, HIV "gets out of the trenches" and begins to intensively copy itself, often returning to the initial scale of infection in three or two weeks. In recent years, scientists have been actively trying to find drugs or antibodies that would help avoid such a "counterattack" of the virus, or would allow the virus to be "kicked out" of cells.
Relatively recently, biologists have found out that the virus "digs in" not only in the T cells that it usually infects, but also in the so-called macrophages – amoeboid cells that destroy bacteria, toxic particles and various "garbage". This discovery forced scientists to embark on a large-scale search for other HIV "bunkers" and methods of smoking the virus out of them.
Erica Borducci from Harvard University (USA) and her colleagues discovered and successfully tested one of the first methods of cleansing the body of latent HIV infection by experimenting on macaques infected with the so–called SHIV - a modified version of the human immunodeficiency virus adapted for life in monkey cells.
A year ago, another group of scientists discovered that a combination of certain antibodies that neutralize many varieties of HIV and SHIV gave a kind of "immunity" to monkeys, forcing their cells to recognize and destroy viral particles even before they penetrate new cells. This did not save them from infection, but protected them from its further expansion.
This discovery prompted Borducci and her colleagues to the idea that such antibodies, in combination with immune stimulants, can help the immune system find traces of the "entrenched" virus and destroy infected cells. Guided by this idea, scientists infected several dozen SHIV macaques and tried to cure them using different combinations of similar drugs.
Combined impact on HIV
These experiments have shown that a combination of two substances has similar properties – the PGT121 antibody, discovered seven years ago in the blood of an HIV-infected person from Africa, and the drug GS-9620, which stimulates the TLR7 gene responsible for activating innate immunity.
A mixture of these two drugs, according to scientists, freed about half of the macaques from all traces of the virus and protected them from the return of infection after stopping taking antiretroviral drugs and injections of GS-9620 and PGT121.
As scientists suggest, such success was due to the fact that the immune stimulator penetrated into T-cells, macrophages and other "bunkers" of HIV and caused a kind of "panic" in the virus, forcing it to synthesize some elements of its shells.
These "fragments" of the virus sometimes got to the surface of the cell membrane, where PGT121 molecules joined them. This allowed the so-called NK cells, the main "killers" of the immune system, to recognize the threat and destroy the infected corpuscles.
The successful completion of these experiments, as noted by Borducci, suggests that antibodies can really be used to "smoke out" HIV from the body in combination with other drugs. Clinical trials with the participation of volunteers, which scientists plan to conduct in the near future, will show whether such therapy also works for people.
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