New
research could help defeat the tenacious gut germ
ASSOCIATED PRESS
July 25
Researchers have discovered that the bacteria that cause ulcers attack
the stomach by grabbing onto cells that are supposed to help the bodys
immune system. Knowing this may help scientists design a vaccine to
block the bugs, researchers believe.
AN ESTIMATED half of the worlds
population is infected with Helicobacter pylori, a tenacious bacteria that
can cause gastritis, stomach ulcers and has been associated with stomach
cancer.
A research team led by Thomas Boren of Umea University in Umea,
Sweden, found that H. pylori has developed a unique method to adhere to the
stomach wall. The findings are published in Fridays issue of the journal
Science.
When the surface of the stomach is first infected it becomes inflamed
and displays a special kind of sugar molecule, called sLex, which normally
serves as a flag to attract immune cells.
The purpose is to signal ... that there is a part of the body that
is in need of help, and that it would now be a good idea to send some more
white blood cells over for assistance, explained Boren.
ADAPTIVE GERM
Unfortunately, he added, H. pylori is most adaptive and has
instead developed tools to utilize the new sugars displayed to its benefit
... for even better adhesion to the stomach cells.
This results in heavier inflammation and peptic ulcer disease, Boren
said.
Advertisement
But because the
special adhesion proteins developed by H. pylori called BabA and SabA
are only made by that bacteria, they may also prove to be its undoing.
This unique trait makes them prime candidates for a vaccine that
would be specific for Helicobacter and would not affect any other bacteria,
Boren said.
Thats important because the gastrointestinal tract contains lots of
bacteria, many of them beneficial.
Co-author Douglas E. Berg of the Washington University School of
Medicine in St. Louis said the findings improve the understanding of the
bodys response to infection and how the bacteria copes with it.
We also hope that understanding how these adhesins work will lead to
a vaccine against H. pylori infections and new drugs to treat or diminish
their activity, he said.
Currently antibiotics are often used to treat H. pylori infections,
but Boren worries that if their use is too widespread, the bacteria will
become resistant.
Boren said the goal is to develop a form of the two adhesion proteins
that will provoke an immune response, preparing the body to recognize them
and use them to target the bacteria for attack. Experiments are under way
using mice, he said.
HUMAN VACCINE YEARS AWAY
Vaccine against Helicobacter and peptic ulcer disease has turned out
to be a challenging task, he said, and even if things go well it would be
six to eight years before the vaccine would be available to people.
The research may also help explain why infection with H. pylori
sometimes seems to become milder and then worsens.
They found that the adhesin allows the bacteria to draw close to the
stomach wall, where it worsens the inflammation. When this attracts more
immune cells, the bacteria can draw away slightly, avoiding the immune
attack and allowing the inflammation to subside and then draw in close
again.
Dr. Stuart A. Thompson of the Medical College of Georgia, who was not
part of the research team, noted that one of the main questions about
Helicobacter is how its able to exist in a state of chronic inflammation in
the stomach.
They have proposed an interesting mechanism where the germs adhere
to the stomach wall, possibly to get nourishment, but can release partway to
avoid immune cells, he said.
ALL INFORMATION, DATA, AND
MATERIAL CONTAINED, PRESENTED, OR PROVIDED HERE IS FOR GENERAL INFORMATION
PURPOSES ONLY AND IS NOT TO BE CONSTRUED AS REFLECTING THE KNOWLEDGE OR OPINIONS
OF THE PUBLISHER, AND IS NOT TO BE CONSTRUED OR INTENDED AS PROVIDING MEDICAL OR
LEGAL ADVICE. THE DECISION WHETHER OR NOT TO VACCINATE IS AN IMPORTANT AND
COMPLEX ISSUE AND SHOULD BE MADE BY YOU, AND YOU ALONE, IN CONSULTATION WITH
YOUR HEALTH CARE PROVIDER.
"A foolish faith in authority is the worst enemy of truth."
-- Albert Einstein, letter to a friend, 1901
"I know of no safe depository of the ultimate powers of the society but the people themselves, and if we think them not enlightened enough to exercise control with a wholesome discretion, the remedy is not to take it from them, but to inform their discretion by education."
-- Thomas Jefferson, letter to William C. Jarvis, September 28, 1820
"What's the point of vaccination if it doesn't protect you from the unvaccinated?"
-- Sandy Gottstein
"Who gets to decide what the greater good is and how many will be sacrificed to it?"