Could a vaginal gel derived from the humble bee’s venom provide the answer to at last effectively end the spread of HIV?
A new study from Washington University’s School of Medicine details how a toxin found in bee venom can, when loaded on specifically tailored nanoparticles, destroy human immunodeficiency virus (HIV) while leaving surrounding cells unharmed.
The potent toxin melittin, which is responsible for the inflammation and pain after a bee sting, has been known to researchers as having potential anti-microbial and anti-fungal properties. The research team wondered whether the toxin would be able to break through HIV’s robust protective layers but knew that large amounts of free melittin can be dangerous as, on its own, the toxin doesn’t discriminate between cells.
As such, researchers decided to shroud the toxin in nanoparticles so as to create what the researchers have termed a “bumper” that rebuffs larger particles like healthy human cells but still lets the smaller virus cells through the nanoparticle buffer, exposing them to the toxin.
Lead researcher Joshua L. Hood, MD, PhD, a research instructor in medicine, explains, “Melittin on the nanoparticles fuses with the viral envelope. The melittin forms little pore-like attack complexes and ruptures the envelope, stripping it off the virus. We are attacking an inherent physical property of HIV. Theoretically, there isn’t any way for the virus to adapt to that. The virus has to have a protective coat, a double-layered membrane that covers the virus.”
Hood emphasizes that attacking HIV in this way damages an essential part of the virus’ structure, something that most anti-HIV drugs, which focus on inhibiting the virus’ ability to replicate, cannot do and so cannot stop the initial infection. Moreover, a number of strains of the virus have now adapted to certain retrovirals and can continue to reproduce.
The team hopes they could create a vaginal gel containing the nanoparticle and melittin combination that would act as an effective barrier method against HIV transmission. Moreover, they are optimistic — though this is an early stage of research — that the method could perhaps be adapted as an intravenous therapy to clear drug-resistant HIV strains from the bloodstream.
As Hood notes, this method is based on research that went into creating an artificial blood product. The outcome in that instance was less successful, but the technique gave scientists a method by which they could begin to develop ways of specifically targeting viruses like HIV.
Researchers point out that melittin is not only effective against HIV. Scientists believe that the treatment could be tailored to target many different viruses, including hepatitis B and C — indeed mostly any virus that relies on the same kind of “protective envelope” that would be vulnerable to melittin-loaded nanoparticles.
Interestingly, while the research did not tackle the issue of turning this treatment toward contraception, in theory the gel could be adapted to target sperm and, perhaps even more interestingly, could be engineered to allow HIV-infected parents to conceive a child and ensure that child remains free of the virus.
The scientists believe that even though this research has only been trialed in a laboratory setting, the nanoparticles will be easy to manufacture to allow for larger clinical trials.
The aim of this is to one day be able to create a low-cost gel that would be able to stop the initial HIV infection. This will be particularly useful where religious and societal stigma has meant that at-risk populations are unwilling to use barrier methods like condoms.
It should be noted that this research, supported by a grant from the the Bill and Melinda Gates Foundation, is only in its very early stages. However, the research comes at a time when research into eradicating HIV is yielding considerable promise, including news that surfaced in the past few weeks of a child who, for the first time in medical history, has been effectively cured of HIV.
The study appears in the current issue of Antiviral Therapy.
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