MARCH 28, 2005
from FIREPAW e-newsletter; visit www.firepaw.org
(Reuters) -- A new chemical compound, part-cat and part-human, may provide an
end to misery-making cat allergies, U.S. researchers reported Sunday.
And they said their approach in
creating the compound may work against more dangerous allergies, such as
deadly peanut allergies.
The compound, tested in mice
bred to be allergic to cats, virtually shut down the histamine reaction that
causes the uncomfortable symptoms of cat allergies such as runny eyes,
sneezing and itching, Dr. Andrew Saxon of the University of California Los
Angeles School of Medicine and colleagues reported.
Writing in the April issue of
Nature Medicine, they said their compound also worked in human cells grown in
"This novel approach to
treating cat allergies is encouraging news for millions of cat-allergic
Americans. Moreover, these results provide proof-of-concept for using this
approach to develop therapies to prevent deadly food allergy reactions as
well," said Dr. Anthony Fauci, director of the National Institute of
Allergy and Infectious Diseases, which paid for the study.
Allergies are caused when the
immune system mistakenly reacts to allergens -- pieces of protein found in
food, on animals or produced by plants. One response is the production of
histamine, which brings on allergy symptoms such as sneezing, wheezing,
itching, watery eyes and sometimes asthma.
The compound stops this
process. It uses pieces of an allergy-provoking protein found in cat saliva or
dander called Fel d1, tied to a piece of human antibody called IgG Fcg1. The
UCLA team named it GFD, or gamma Feline domesticus.
The cat allergen part attaches
to antibodies on the surface of the immune system cells that produce
histamine, while the human bit stops the cell from getting started.
"We measured more than 90
percent less histamine in the (human cell) cultures with GFD," Saxon
said. "Those results suggested that GFD successfully prevented the immune
cells from reacting to cat allergen. The next step was to test GFD in mice
that we had made allergic to the allergenic protein found in cat saliva and
The researchers tested GFD in
two types of allergic mice, and it blocked the immune over-response in both.
The approach could be used to
protect people from a wide array of allergies, the researchers said.