http://www.cnn.com/2005/HEALTH/conditions/03/28/cat.allergies.reut/index.html

Report: Compound may end cat allergies

WASHINGTON (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 lab dishes.
"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 dander."
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.