Scientists say they're hopeful that a research breakthrough will lead to a cure for people who are allergic to cats.
Researchers at the University of Cambridge say they've figured out how a particular protein in cat dander triggers an allergic response in humans. Many people are allergic to cats, dogs, and other animals. Typical symptoms include sneezing, itchiness, and a stuffed or runny nose. Allergic reactions happen when the immune system overreacts to a perceived danger. Normally, the immune system identifies and responds to harmful viruses and bacteria. But with an allergy, the immune system wrongly identifies an allergen as dangerous, such as pet dander, and starts an immune response.
The most common cause of severe allergic reactions to cats is a protein called Fel d 1, which is found in microscopic pieces of animal skin (often accompanied by dried saliva) from grooming.
The Cambridge team discovered how this protein can trigger an inflammatory response when in the presence of a common bacterial toxin found in the environment called lipopolysaccharide, or LPS.
"How cat dander causes such a severe allergic reaction in some people has long been a mystery," said Clare Bryant, who led the research at the University of Cambridge’s Department of Veterinary Medicine. "Not only did we find out that LPS [intensifies] the immune response’s reaction to cat dander, we identified the part of immune system that recognizes it, the receptor TLR4."
The scientists then used medication that curbs the TLR4 response and found it blocks the effects of the cat dander protein on human cells, thereby preventing an inflammatory response.
Bryant says she's hopeful that the research will lead to new treatments for people with cat allergies, and possibly those with dog allergies.