Scientists study vaccines against biological weapons
A microbiologist at
The University of Texas Health Science Center at San Antonio (UTHSC) is
working out new vaccines for anthrax and tularemia, two potential biological
weapons that could wipe out military and civilian populations.
Karl Klose, Ph.D., assistant
professor of microbiology, has received $1.5 million from the National
Institutes of Health to pursue the studies, which could lead to oral vaccines
for the dangerous infections within five years. Study collaborators include
Kent Lohmann, Ph.D., of Brooks Air Force Base, Jean Patterson, Ph.D.,
of the Southwest Foundation for Biomedical Research, and John Gunn, Ph.D.,
assistant professor of microbiology at UTHSC.
Anthrax, a common soil
bacterium, is considered the ideal bioterrorism weapon because of the
potential ease with which it could be spread. It is a sneaky killer, beginning
with flu-like symptoms that are difficult to diagnose. A terrorist
could be on a plane and out of the country before anyone knew what happened,
Dr. Klose said.
Anthrax, once breathed
in, releases a toxin that can kill up to 80 percent of victims. Tularemia
can kill approximately 60 percent. Dr. Klose and his colleagues hope to
spur the bodys immune system to knock out these bacteria before
they cause damage. The researchers are looking to help from an unlikely
source Salmonella, a bacterium that causes food poisoning.
Drs. Klose and Gunn
have studied the characteristics of Salmonella for a number of years,
and they believe it can be adapted to serve as a delivery system for anthrax
and tularemia vaccines. We have crippled the Salmonella strain so
that it can live in the intestine without causing disease, Dr. Klose
said. Next, we want to insert a small piece of anthrax the
portion that comprises the current injectable vaccine into the
Salmonella. We will vaccinate mice and other animals and monitor them
to see if they develop resistance to anthrax or tularemia.The work
will be performed in a Level 4 biocontainment facility at the Southwest
Foundation for Biomedical Research. Brooks AFB personnel will test the
vaccinated animals to make sure they are expressing immunity to anthrax
Often associated with
sheep and cattle, anthrax usually infects only the skin, causing black
boils that are treatable. When breathed in, however, the bacterium multiplies
and manufactures its toxin. Flu-like symptoms soon appear, followed by
complete organ failure and death.
thing about both anthrax and tularemia is that they can live inside macrophages,
which are the cells that repel foreign invaders from our bodies,
Dr. Klose said. Anthrax and tularemia use macrophages as taxis
to travel inside the body and multiply.
The specter of bioterrorism
looms larger in the wake of the Sept. 11 terror attacks on New York and
Washington. New vaccines for anthrax and tularemia could save the lives
of millions in the event a terrorist tries to disseminate these bioweapons.
The U.S. military instituted
mandatory anthrax vaccinations for its personnel after the Gulf War. The
current vaccine is effective but requires a series of six injections.
Some military personnel have objected to the vaccine because it can cause
serious reactions after the third or fourth injection, including flu-like
symptoms and vision distortions. Were trying to develop a
safer, less expensive and more effective vaccine that would be easy to
administer and that would protect people against biowarfare, Dr.
Klose said. A terrorist act using anthrax is probably only a matter
Dr. Klose has organized
a bioterrorism symposium as part of the annual meeting of the Texas Branch
of the American Society for Microbiology. Five scientific experts studying
potential bioterrorist threats will give the session, which is scheduled
for 8 a.m. to noon Nov. 17 at the Sheraton Gunter Hotel. The cost is $10
per person and the public is invited.
Contact: Will Sansom
or Aileen Salinas