(CBS NEWS) -- Do your eyes water at the sight of a furball? Can you only enjoy a feline friend without sneezing through a YouTube video?
say they have figured out why cats are making your allergies crazy --
and their research might also help those allergic to dogs as well.
allergic reaction is really just the body overreacting to what it
thinks is a bacteria or virus. The body confuses the allergen (like
pollen or peanuts) as a substance that will harm it, so it mounts an
unnecessary full-blown immune system defense to get it out. This results
in sneezing, wheezing, scratching and all kinds of unpleasant symptoms
we associate with allergies.
Cat protein Fel D1 -- also known as
cat dander -- has been known to trigger severe allergic reactions.
Since cat hair gets everywhere, it's hard to avoid. Before the study,
scientists didn't know why it triggered responses in people.
scientists found that when Fel D1 comes in contact with a common
bacteria toxin called lipopolysaccharide (LPS), it activates a receptor
that recognizes the pathogen called Toll-like receptor 4 (TLR4). TLR4 is
also the receptor that causes the allergic response to dust mites and
the metal nickel. When TLR4 is turned on, it beefs up the body's immune
system response to Fel D1. The response continues to grow, and the
person's allergic symptoms become worse.
"How cat dander causes
such a severe allergic reaction in some people has long been a mystery,"
lead author Dr. Clare Bryant, from the University of Cambridge's
Department of Veterinary Medicine, said in a press release.
"Not only did we find out that LPS exacerbates the immune response's
reaction to cat dander, we identified the part of immune system that
recognizes it, the receptor TLR4."
Researchers then exposed
human cells to a drug that stops the TLR4 response. It was able to block
out the cells' reaction to dander protein.
The researchers also
discovered that a different protein, Can F6 -- dog dander, which causes
allergic reactions to dogs -- also was enhanced by the presence of LPS.
Together, they triggered TLR4.
"As drugs have already been
developed to inhibit the receptor TLR4, we are hopeful that our research
will lead to new and improved treatments for cat and possibly dog
allergy sufferers," Bryant added.
Allergy UK director of clinical services Maureen Jenkins, told the BBC
that this research was important in order to figure out a way to get
rid of cat and dog allergies in humans -- which would be the cat's meow.
allergen is particularly difficult to avoid as it is a 'sticky'
molecule that is carried into every building on people's shoes and
clothes," Jenkins explained. "It can also still be found in a home, on
the walls and ceiling or fittings, even a few years after a cat has
ceased to live there. Therefore, this new information identifying the
specific receptor interaction in the immune system could pave the way
for treatments for those with persistent disease triggered by cat
allergen and, in the future, potentially dog and house dust mite
The study was published in the The Journal of Immunology on July 22.