In a breakthrough study against the virus that causes AIDS, scientists have identified a new HIV-agent that could create an effective vaccine in the future.
The new drug candidate successfully blocks every strain of HIV-1, HIV-2 and SIV (simian immunodeficiency virus) that has been isolated from humans or rhesus macaques, including variants that are notoriously difficult to stop. What's more, it protects against much-higher doses of HIV than occur in most humans, and for a staggering eight months after injection. These results are promising in the fight against HIV and AIDS.
"Our compound is the broadest and most potent entry inhibitor described so far," researcher Michael Farzan, who led the research, said in a statement. "Unlike antibodies, which fail to neutralize a large fraction of HIV-1 strains, our protein has been effective against all strains tested, raising the possibility it could offer an effective HIV vaccine alternative."
The way HIV infects a cell is it targets the CD4 lymphocyte, a type of white blood cell that is part of our body's immune system. HIV merges with a host cell and inserts its own genetic material, transforming what was once a normal cell into a HIV-manufacturing machine. It is also well known among scientists that a co-receptor called CCR5 contains proteins that are critical when HIV binds to the cell site, however these proteins can be targeted to prevent infection.
A team from the Jupiter, Florida campus of The Scripps Research Institute (TSRI) capitalized on this fact when creating their new anti-HIV agent. The potential vaccine essentially copies the CCR5 co-receptor's proteins by binding to two sites on the surface of the virus simultaneously, and preventing HIV from entering the host cell.
"When antibodies try to mimic the receptor, they touch a lot of other parts of the viral envelope that HIV can change with ease," explained first study author Matthew Gardner. "We've developed a direct mimic of the receptors without providing many avenues that the virus can use to escape, so we catch every virus thus far."
So how exactly do the researchers deliver this HIV-killing system to the body? They inject a non-disease-causing virus into muscle tissue - much like HIV itself - and turn those muscle cells into "factories" that can produce enough of the new effective proteins to last for years, perhaps decades.
This remarkable advance is so potent and universally effective that it just might become an unconventional vaccine in the near future.
The findings are described further in the journal Nature.
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