Medical Discovery News
By Norbert Herzog and David Niesel

People with cat allergies who still love cats — and their cat-allergic friends, family, spouses and roommates — may soon find relief through a new vaccine.

Microscopic pieces of shed — dry cat skin coated with a protein called Fel d1 — are responsible for most cat allergies. This protein is secreted from various glands, then ends up on fur, from which it passes to furniture, clothing and the air.

It is the most potent allergen in cat dander to which 95 percent of people with cat allergies react. Cat allergies affect about 10 percent of the western world. An estimated 14 percent of children between the ages of 6 and 19 years old are allergic to cats.

The Fel d1 protein can cause a bad reaction in some humans. Normally, the body treats it as any other antigen or foreign substance. As it’s no threat, the body usually ignores or removes it.

But in someone with a cat allergy, the immune system overreacts to Fel d1, making an antibody called immunoglobin E (IgE).

The next time the person encounters the protein, the body releases the IgE antibodies much more quickly and in greater amounts. These antibodies then trigger a release of histamines, which relax capillaries and smooth muscles, affecting the soft tissue areas around the eyes, nose and throat.

So allergy sufferers end up with watery eyes, runny noses, sneezing and scratchy throats. Symptoms range from these mild reactions to asthma or even life-threatening anaphylactic shock.

When someone with cat allergies encounters one of the 93.6 million cats in the United States, they can treat the symptoms with antihistamines, decongestants or prescription steroids.

Some opt for immunotherapy or allergy shots to desensitize themselves to the cat allergens but that involves many shots over weeks, months or even years.

Hypoallergenic cats have been bred by a company called Allerca, but they are very expensive, ranging in price from $7,000 to $27,000.

Now cat allergy sufferers have another option. A vaccine has been developed by an Oxford-based company called Cicassia that consists of seven peptides, short pieces of the Fel d1 protein. These peptides will appease the cellular part of the immune response while not activating the part that leads to allergic reactions.

The ToleroMune vaccine successfully passed both Phase 1 and Phase 2 clinical trials and is in a Phase 3 clinical trial. The vaccine was shown to significantly reduce nose- and eye-related symptoms in response to cat dander.

This gives hope to those who love someone with a cat but don’t love the cat allergy symptoms, and to cat owners who don’t want to choose between their furry friend and someone allergic to it.

Professors Norbert Herzog and David Niesel are biomedical scientists at the University of Texas Medical Branch. Learn more at medicaldiscoverynews.com.