Not all biological weapons are
created equal. They are separated into categories A through C, category
A biological agents being the scariest: They are easy to spread, kill
effectively and call for special actions by the pubic health system.

One of these worrisome organisms is anthrax, which has already received
its fair share of media attention. But work in Vince Fischetti’s
laboratory at Rockefeller University suggests that a newly discovered
protein could be used to fight anthrax infections and even
decontaminate areas in which anthrax spores have been released.

“Anthrax is the most efficient biowarfare agent. Its spores are
stable and easy to produce, and once someone inhales them, there is
only a 48-hour window when antibiotics can be used,” says Fischetti.
“We’ve found a new protein that could both potentially expand that
treatment window and be used as a large-scale decontaminant of anthrax
spores.” Because anthrax spores are resistant to most of the chemicals
that emergency workers rely on to sterilize contaminated areas, a
solution based on the protein would be a powerful tool for cleaning up
after an anthrax attack.

All bacteria, anthrax included, have natural predators called
bacteriophage. Just as viruses infect people, bacteriophage infect
bacteria, reproduce, and then kill their host cell by bursting out to
find their next target. The bacteriophage use special proteins, called
lysins, to bore holes in the bacteria, causing them to literally
explode. Fischetti and colleagues identified one of these lysins,
called PlyG, in 2004, and showed that it could be used to help treat
animals and humans infected by anthrax. Now, they have identified a
second lysin, which they have named PlyPH, with special properties that
make it not only a good therapeutic agent, but also useful for
large-scale decontamination of areas like buildings and military
equipment.

The new protein has several advantages. Most lysins, including PlyG,
are only active in a very specific pH range of six to seven, so that
they work very effectively in our bloodstream, but may not useful in
many environmental conditions. “PlyPH works in an extremely wide pH
range, from as low as four to as high as eight,” says Fischetti. “I
don’t know of any other lytic enzyme that has such a broad range of
activity.”

In addition, PlyPH, like PlyG, is highly specific in terms of the
types of bacteria it affects. When Fischetti and colleagues added PlyPH
to different bacterial species, only the anthrax bacteria were killed.
This is a great benefit over antibiotics, which kill many different
kinds of bacteria, including many helpful species. Because it is so
specific, the chances of anthrax becoming resistant to PlyPH, as it is
to many of the antibiotics currently available to treat it, are
extremely low.

“We have never seen bacterial resistance to a lysin,” says
Fischetti. “PlyPH and PlyG are probably the most specific lysins we, or
anyone, has ever identified — they only kill anthrax and its very close
relatives. This feature, and the wide pH range offered by PlyPH, is why
we think it could be used as an environmental decontaminant.”

Fischetti hopes to combine PlyPH with a non-toxic aqueous substance
developed by a group in California that will germinate any anthrax
spores it comes in contact with. As the spores germinate, the PlyPH
protein will kill them, usually in a matter of minutes. The combined
solution could be used in buildings, on transportation equipment, on
clothing, even on skin, providing a safe, easy way to fight the spread
of anthrax in the event of a mass release.

sciencedaily.com