Nanoparticles Loaded With Bee Venom Kill HIV
Concept can be applied to other viruses, including hepatitis C (Mar. 7)
Nanoparticles carrying a toxin found in bee venom can destroy human immunodeficiency virus (HIV) while leaving surrounding cells unharmed, according to research conducted at the Washington University School of Medicine in St. Louis, Missouri. The new finding is an important step toward developing a vaginal gel that may prevent the spread of HIV, the investigators say.
The study was published in Antiviral Therapy.
Bee venom contains melittin, a potent toxin that can poke holes in the protective envelope that surrounds HIV and other viruses. In addition to anti-viral therapy, the researchers have found that melittin-loaded nanoparticles are effective in killing tumor cells.
The new study showed that melittin loaded onto nanoparticles does not harm normal cells. That’s because the researchers added protective “bumpers” to the nanoparticles’ surfaces. When the particles come into contact with normal cells, which are much larger, the particles simply bounce off. HIV, on the other hand, is smaller than a nanoparticle. As a result, the HIV fits between the “bumpers” and makes contact with the surface of the nanoparticle, where the bee toxin is located.
“Melittin on the nanoparticles fuses with the viral envelope,” explained researcher Joshua L. Hood, MD, PhD. “The melittin forms little pore-like attack complexes and ruptures the envelope, stripping it off the virus.”
According to Hood, an advantage of this approach is that the nanoparticle attacks an essential part of the virus’ structure. In contrast, most anti-HIV drugs inhibit the virus’s ability to replicate — but this anti-replication strategy does nothing to stop initial infection, and some strains of the virus have found ways around these drugs and reproduce anyway.
“We are attacking an inherent physical property of HIV,” Hood says. “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.”
In addition to HIV prevention in the form of a vaginal gel, Hood also sees a potential for using nanoparticles with melittin as therapy for existing HIV infections, especially those that are drug-resistant. The nanoparticles could be injected intravenously and, in theory, would be able to clear HIV from the bloodstream, he says.
Since melittin attacks double-layered membranes indiscriminately, this concept is not limited to HIV. Many viruses, including hepatitis B and C, rely on the same kind of protective envelope and would be vulnerable to melittin-loaded nanoparticles.
While the new research was done in cells in a laboratory environment, Hood and his colleagues say the nanoparticles are easy to manufacture in large enough quantities to supply them for future clinical trials.
Source: Washington University School of Medicine; March 7, 2013.