New tack in fighting diseases

Eric Berger on the Houston Chronicle covers an amazing breakthrough in medical research at the University of Texas M.D. Anderson Cancer Center:

...The aerosol — a purified extract of a common bacterium — stimulates the
lungs to vigorously reject pathogens. In addition to finding a bacterium that's
effective for this purpose, the method of delivering it directly to the lungs is
important so that the bacterium can boost the immunse system.

Unlike vaccines, which must typically be given a week or more before
exposure, the new aerosol is highly effective against a host of pathogens —
including anthrax, influenza and even bubonic plague — if given just a few hours
before infection. The new drug and its delivery system even have some benefit if
given after exposure.

"Our idea was, why not strengthen the immune system in the body's
lungs," said Dr. Burton Dickey, chair of pulmonary medicine at M.D. Anderson and
a leader of the research.

"We decided to try and kill all the pathogens in the lungs, the body's
first line of defense, before they penetrate into the rest of the body. We've
found that we can very dramatically ramp up the defenses of the lungs."

The new aerosol targets the innate immune system, which is different
from the adaptive immune system that most people are more familiar with.
Vaccines — which teach the body to build up antibodies, then recognize and
destroy invaders — target the adaptive immune system. Only higher vertebrates,
such as birds and mammals, have this component of the immune system.

More common to all life is the innate immune system, which doesn't
recognize specific invaders, but rather generally recognizes and reacts to all
pathogens in a generic way.

The approach by M.D. Anderson scientists to the pathogens is novel in
that it seeks to bolster the innate, rather than the adaptive, immune system.
They presented their study results today at the annual meeting of the American
Society of Cell Biology in Washington, D.C.

"The aerosol stimulates an innate immune system response in the lung
lining that kills the invading pathogens, virtually on contact," said Brenton
Scott, a researcher in Dickey's lab who led the study.

In their experiments, the scientists let mice breathe the special,
aerosolized bacteria for 20 minutes. Then, within four to 24 hours, the mice
were exposed to various pathogens.

After that, all of the mice exposed to the Staphylococcus aureus
bacterium survived, as did 90 percent of those exposed to influenza A, 60
percent of those exposed to the plague and 30 percent exposed to another
potential bioterror agent, tularemia, survived.

Unlike a vaccine, which confers long-term protection, the aerosol
provides protection for only a few days.