AN important step toward developing a vaginal gel that may prevent
the spread of human immunodeficiency virus, HIV, may have been achieved
following the discovery that nanoparticles carrying a toxin found in bee
venom can destroy HIV while leaving surrounding cells unharmed.
Researchers at Washington University School of Medicine in St. Louis
who made discovery which is published the current issue of Antiviral
Therapy, hope that in places where HIV is running rampant, people could
use this gel as a preventive measure to stop the initial infection.
Bee venom contains a potent toxin called melittin that can poke holes
in the protective envelope that surrounds HIV, and other viruses. Large
amounts of free melittin can cause a lot of damage. Indeed, in addition
to anti-viral therapy..
The new study shows that melittin loaded onto these nanoparticles
does not harm normal cells. That’s because Hood added protective bumpers
to the nanoparticle surface. When the nanoparticles come into contact
with normal cells, which are much larger in size, the particles simply
bounce off. HIV, on the other hand, is even smaller than the
nanoparticle, so HIV fits between the bumpers and makes contact with the
surface of the nanoparticle, where the bee toxin awaits.
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.
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.
The scientists, who say they are attacking an inherent physical
property of HIV, note that, 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.
Beyond prevention in the form of a vaginal gel, there is 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 blood stream.
The basic particle that we are using in these experiments was
developed many years ago as an artificial blood product. Although it
didn’t work very well for delivering oxygen, but it circulates safely in
the body and gives nice platform that can be adapted to fight
different kinds of infections.
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.
Social Plugin