Scientists at The Scripps Research Institute (TSRI) in Jupiter, Florida, recently developed a new drug candidate that is so powerful against HIV that it may prove efficient in vaccine form.
Research demonstrates that the new treatment effectively blocks all strains of HIV-1, HIV-2, and SIV (simian immunodeficiency virus), even the most resistant mutations of the strains. The vaccine prevents humans from contracting HIV, even after exposure to unusually high doses of the virus, for approximately eight months after they receive the injection.
When HIV first attacks a cell, it anchors into CD4 lymphocyte, an important key in the human immune system. Then HIV injects its genetic material into the cell through RNA and makes the cell a HIV home base.
Researchers used preexisting studies conducted by in the lab of Michael Farzan, a TSRI professor who led the most recent research as well. The studies showed protective proteins can be used to inhibit the CCR5 co-receptor region. This is a critical point in fighting against HIV infections. Farzan’s research team created a treatment that fuses to two sites on the surface of HIV cells, inhibiting HIV from entering into the host cell.
The scientists used preexisting technology to create an adeno-associated virus (a virus that does not cause diseases). This technology mimics HIV behavior in that it uses host cells as home bases to reproduce its genetic material through RNA. This helps the vaccine reproduce its protective protein for years and maybe even decades.
"When antibodies try to mimic the receptor, they touch a lot of other parts of the viral envelope that HIV can change with ease," Matthew Gardner, TSRI Research Associate Matthew Gardner and the first author of the study with Lisa M. Kattenhorn of Harvard Medical School, said. "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."
Scientists from more than a dozen institutions took part in the research, which was published today on the online version of Nature.
“This is the culmination of more than a decade's worth of work on the biochemistry of how HIV enters cells," Farzan said. "When we did our original work on CCR5, people thought it was interesting, but no one saw the therapeutic potential. That potential is starting to be realized."