About 3.2 million cats in the United States are brought to animal shelters each year, for “pet problems,” allergies being one of the more common pet problems that leads to surrender. Fortunately, Switzerland-based HypoPet AG has a cat allergy vaccine in development that has promising preliminary results. The vaccine, marketed as HypoCat™, is not for humans but for cats, and would induce antibody production in cats against their most common cat allergen to humans, Fel d 1.
Is this the answer to these heartbreaking decisions? Will this vaccine break down some of the barriers to cat adoption? In order to determine that, we need to have a basic understanding of Fel d 1 transmission, and how this vaccine would work. There are a total of 10 allergens produced by cats; however, the most important one is Fel d 1 (of the 10% of Americans being allergic to cats, between 80-90% of them are allergic to Fel d 1). The protein is found in cats’ saliva, tears, and perianal and sebaceous glands. A 2018 review of cat allergens mentioned that sebaceous glands are a primary location of Fel d 1 production.
Features of Vaccine For Cat Allergies
HypoPet, which spun off from research conducted at the University of Zurich in 2014, aims to prevent household cats from producing a key allergen called Fel d 1. It’s a protein produced in various cat glands and is found in their saliva and on their skin. Fel d 1 is the primary cause of allergic reactions to cats among humans. HypoPet is working on an experimental vaccine called Fel-CuMV (or HypoCat), which incorporates particles from the cucumber mosaic virus attached to a Fel d 1 protein. The vaccine tricks the cat’s immune system into recognizing the protein as a foreign intruder. This induces the production of antibodies that neutralize the Fel d 1 proteins, essentially eliminating their presence in the cat’s body.
Although HypoPet has been developing this treatment since 2014, in the past year they’ve made accelerated progress toward their vaccine. In July 2019, they published a paper in the Journal of Allergy and Clinical Immunology reporting the results of a number of studies they did on the vaccine’s effects on 70 cats, showing that it successfully induced a sustained antibody response in the felines. They also noted that cat saliva samples contained lower concentrations of the allergenic protein, and that overall, the vaccine didn’t seem to harm the animals.
Another preventative method for cat allergies is to delete the gene that produces Fel d 1 proteins altogether, effectively making the cat completely hypoallergenic. This method is being tested by a Virginia-based company, Indoor Biotechnologies, which researches and develops tools to measure different types of indoor allergens. President and CEO Martin Chapman, a former professor of microbiology at University of Virginia, says the company has been researching CRISPR gene-editing software in cats for the last two years.
The project, known as CRISPR Cat, is being led by biologist Nicole Brackett. Brackett says her research started by sequencing Fel d 1 from 50 cat tissue samples, and finding DNA regions that were consistent among the cats and were suitable to test CRISPR editing on. Brackett then tested the CRISPR technology on a feline kidney cell line, using 10 different synthetic RNA guides targeting the genes that produce Fel d 1. The project ended with a 50 to 55 percent success rate in editing the genes out of the samples. Because the team was only working with cells, no cats were harmed.
Cat Allergy Treatments
If avoiding cats isn’t possible, or you just really, really want a cat despite an allergy, Blaiss recommends at a minimum to never allow the cat inside your bedroom, where you spend about eight hours a day. Products such as antihistamines, nasal steroids and asthma medications can provide some relief. But medications treat symptoms, not the cat allergy itself. To do that, you need immunotherapy, which is given as shots in an allergist’s office.
Immunotherapy retrains the immune system to tolerate more cat protein without reacting. Typically, patients go to an allergist’s office for weekly injections with small amounts of cat protein during a buildup phase that lasts for several months. That’s followed by monthly “maintenance” injections for three to five years. Research shows that cat immunotherapy can reduce symptoms in many people, and that the results last. But some people react to the injections, while others quit because of the inconvenience of as many as 80 injections in all. A lot of people quit before three years. There really is a need to get the duration of it down,” says Dr. Harold Nelson, an allergist at National Jewish Health in Denver.
Prices of Vaccine For Cat Allergies