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Last Updated: Apr 20, 2011 - 9:38:09 AM |
U.S. Department of Health and Human Services
NATIONAL INSTITUTES OF HEALTH NIH News
National Institute of Allergy and Infectious Diseases (NIAID) <http://www.niaid.nih.gov/>
For Immediate Release: Monday, January 12, 2009
CONTACT: Julie Wu, 301-402-1663, <e-mail: wujuli@niaid.nih.gov>
OF MICE AND PEANUTS: A NEW MOUSE MODEL FOR PEANUT ALLERGY
Chicago researchers report the development of a new mouse model for
food allergy that mimics symptoms generated during a human allergic
reaction to peanuts. The animal model provides a new research tool that
will be invaluable in furthering the understanding of the causes of
peanut and other food allergies and in finding new ways to treat and
prevent their occurrence, according to experts at the National
Institute of Allergy and Infectious Diseases (NIAID), the component of
the National Institutes of Health (NIH) that funded the research.
Peanut allergy is of great public health interest because this food
allergy is the one most often associated with life-threatening allergic
reactions, resulting in up to 100 deaths in the United States each year.
The findings of the research team, led by Paul Bryce, Ph.D., of the
Feinberg School of Medicine at Northwestern University, appear in the
January issue of the Journal of Allergy and Clinical Immunology. The
development of new animal models for food allergy was identified as a
critical need by the 2006 NIH Expert Panel on Food Allergy Research.
"Food allergies affect the health and quality of life of many
Americans, particularly young children," says NIAID Director Anthony S.
Fauci, M.D. "Finding an animal model that mimics a severe human
allergic reaction to peanuts will help us better understand peanut
allergy and develop new and improved treatment and prevention
strategies."
Allergic reactions to food can range from mild hives to vomiting to
difficulty breathing to anaphylaxis, the most severe reaction.
Anaphylaxis may result from a whole-body allergic reaction to the
release of the chemical histamine, causing muscles to contract, blood
vessels to dilate and fluid to leak from the bloodstream into the
tissues. These effects can result in narrowing of the upper or lower
airways, low blood pressure, shock or a combination of these symptoms,
and also can lead to a loss of consciousness and even death.
The most significant obstacle to developing an animal model of food
allergy is that animals are not normally allergic to food. Scientists
must add a strong immune stimulant to foods to elicit a reaction in
animals that resembles food allergy in humans. Because of this
requirement, useful animal models have been developed only in the last
few years, and such animal models have until now used cholera toxin as
the immune stimulant.
Dr. Bryce's team took the novel approach of feeding mice a mixture of
whole peanut extract (WPE) and a toxin from the bacteria Staphylococcus
aureus, called staphylococcal enterotoxin B (SEB) to simulate the human
anaphylactic reaction to peanuts in mice.
"Persistent S. aureus colonization is commonly found on the skin of
people with eczema and in the nasal cavities of people with sinusitis,"
says Dr. Bryce. "The history between S. aureus and allergic diseases
led us to use staphylococcal toxins to stimulate food allergy in
animals."
According to Dr. Bryce, the results using the SEB/WPE mixture were
considerably better than those seen with previous animal models, which
failed to mimic many features of food allergy. They showed that the
SEB/WPE mixture stimulated severe symptoms in mice that closely
resemble those found in human anaphylaxis, including swelling around
the eyes and mouth, reduced movement and significant problems
breathing. Additionally, mice given the SEB/WPE mixture had high blood
levels of histamine, which indicates a severe allergic reaction.
The researchers also observed that the blood and tissues of mice in the
SEB/WPE group had higher-than-normal numbers of eosinophils, which are
white blood cells often associated with allergy-related inflammation.
Future studies will be needed to determine if eosinophils play an
important role in human food allergy.
These results, say Dr. Bryce, suggest that this animal model of food
allergy will be useful for many types of future research studies.
Approximately 4 percent of Americans have food allergies. For reasons
that are not well understood, the prevalence in children increased by
18 percent between 1997 and 2007. The most common causes of food
allergies are milk, eggs, shellfish, peanuts, tree nuts, wheat and soy.
Each year there are between 15,000 and 30,000 episodes of food-induced
anaphylaxis, which are associated with 100 to 200 deaths in the United
States.
NIAID is the lead institute at NIH for research in food allergy and
supports basic research in allergy and immunology to understand how
foods trigger an allergic reaction. NIAID also conducts clinical
trials that are attempting to alter the body's immune response so that
it does not trigger allergic reactions to food.
NIAID conducts and supports research -- at NIH, throughout the United
States, and worldwide -- to study the causes of infectious and
immune-mediated diseases, and to develop better means of preventing,
diagnosing and treating these illnesses. News releases, fact sheets and
other NIAID-related materials are available on the NIAID Web site at
<http://www.niaid.nih.gov>.
The National Institutes of Health (NIH) -- The Nation's Medical
Research Agency -- includes 27 Institutes and Centers and is a
component of the U.S. Department of Health and Human Services. It is
the primary federal agency for conducting and supporting basic,
clinical and translational medical research, and it investigates the
causes, treatments, and cures for both common and rare diseases. For
more information about NIH and its programs, visit <www.nih.gov>.
REFERENCE: K Ganeshan et al. Impairing oral tolerance promotes allergy
and anaphylaxis: a new murine food allergy model. "Journal of Allergy
and Clinical Immunology." DOI: 10.1016/j.jaci.2008.10.011 (2008).
##
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