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By Scott Sutherland | Geekquinox – Thu, 25 Jul, 2013

Allergic to cats? Relief is now on the way after a team of scientists from the UK, Sweden and the United States narrowed down exactly how cat dander sets off such a strong reaction in those who are allergic to it.

We’ve known for a long time what causes cat allergies. The cat licks its fur as it cleans itself, and proteins from the cat’s saliva end up on its dandruff (or dander). The dander flakes off onto the carpet or the couch or whatever else the cat lies on. When that surface gets disturbed, the dander gets up into the air, we breath it in, and it’s time for the itchy, watery eyes and sneezing, and a trip to the medicine cabinet for some anti-histamines.

However, whereas we knew that much of it, it wasn’t clear exactly how that protein from the cat’s saliva — called Fel d 1 — caused such a strong reaction. This research, led by University of Cambridge veterinary researcher Dr. Clare Bryant, has now figured out that when Fel d 1 comes into contact with common environmental bacteria, the protein becomes ‘contaminated’ by molecules in the bacteria’s cell wall called lipopolysaccharides. Lipopolysaccharides (LPS) are detected by receptors in our bodies called Toll-like receptor 4 (TLR4), that active the ‘first line of defense’ part of our immune system, so their presence with the Fel d 1 protein causes an increased response from our body.

By introducing a drug that inhibits that TLR 4 response, the researchers were able to prevent the allergic reaction.

“How cat dander causes such a severe allergic reaction in some people has long been a mystery,” Dr. Bryant said in a University of Cambridge news 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.”

“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,” Dr. Bryant added.

Since TLR4 is involved in other allergic reactions as well, such as to dogs, dust mites and nickel, the research team hopes that the medication that will result from this study can be used for those, but it might not end there.

Some people who have allergies to cats also have allergies to pork.

This ‘pork-cat syndrome‘ is known as a ‘cross allergy‘ — when a particular allergen can come from different sources, or if the antibodies for an allergen start to react to the presence of other, very similar allergens. For pork-cat syndrome, it was found the allergy sufferers were reacting to a protein common to both cat dander and pork — called albumin. Whereas this is a different protein than Fel d 1, since it’s common for the body to become hypersensitive to other allergens once it’s started to react to one, it’s possible that those who suffer from this syndrome are having a reaction to albumin in addition to the reaction to Fel d 1. Therefore, this cure based on Fel d 1 could also give allergy sufferers the opportunity to eat pork as well.

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