Scientists from The Scripps Research Institute (TSRI) in Jupiter, Florida have announced the creation of a novel drug candidate against HIV so potent and effective that the discovery could work as part of an unconventional vaccine for HIV.
HIV, or human immunodeficiency virus, causes the acquired immunodeficiency syndrome (AIDS), a serious health condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive. Medication can treat and control infection, but no cure currently exists. HIV spreads through the transfer of blood, semen, vaginal fluid, pre-ejaculate, and breast milk.
The new research published in the journal Nature demonstrates the way in which the new drug candidate blocked every strain of HIV-1, HIV-2, and SIV (simian immunodeficiency virus), including the variants most difficult to block. The drug additionally offers protects against doses of the virus higher than normally occur in human transmission for at least eight months after injection.
Says Michael Farzan, a Scripps Research Institute professor who led the research:
“Our compound is the broadest and most potent entry inhibitor described so far. 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.”
HIV infects a host cell by inserting its own single-stranded RNA into the cell. The new drug builds on previous research by Farzan laboratory that proteins based on a critical HIV-binding region can prevent infection with the virus. The researchers used the knowledge to create a new drug that binds to two sites on the surface of the virus simultaneously, thus preventing entry of HIV into a host cell.
Says first author Matthew Gardner, TSRI Research Associate, with Lisa M. Kattenhorn of Harvard Medical School:
“When antibodies try to mimic the receptor, they touch a lot of other parts of the viral envelope that HIV can change with ease. 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.”
The researchers also developed a delivery mechanism for the drug candidate using an engineered adeno-associated virus, which is a small, relatively harmless virus that does not cause disease. The adeno-associated virus turns cells into manufacturing sites that churn out enough of the new protective protein to potentially last for decades.
Comments Farzen on the findings:
“This is the culmination of more than a decade’s worth of work on the biochemistry of how HIV enters cells. 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.”
The findings of the present research may aid in the development of an HIV vaccine.
AAV-expressed eCD4-Ig provides durable protection from multiple SHIV challenges: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14264.html#close
Potential new vaccine ‘blocks all known strains of HIV’: http://www.medicalnewstoday.com/articles/289611.php
Scripps Research Institute Scientists Announce Anti-HIV Agent So Powerful It Can Work in a Vaccine: http://www.newswise.com/articles/scripps-florida-scientists-announce-anti-hiv-agent-so-powerful-it-can-work-in-a-vaccine
Potential New HIV Vaccine: https://www.flickr.com/photos/8499561@N02/2755481069/