Fel d 1 Protein Sparking Curiosity that Could Change the Cat

Nicole Brackett, postdoctoral fellow at Indoor Biotechnologies, sequenced Fel d 1 from her cat Taco, pictured here / photo courtesy of Nicole Brackett.

More than 50 million cats roam the homes of more than 20 million Americans. For many people, cats are cuddly, curious companions, but for at least 10% of adults they mean itchy skin, watery eyes and sneezing – basically constant misery. This is largely due to a protein called Fel d 1, and scientists are using different approaches to try to change it.

Fel d 1 is mainly produced in saliva, skin, fur, anal and sebum glands. Cats spread it while performing their extensive cleansing rituals and while shedding fur and flakes of skin. It is the leading cause of allergic reactions in cats, which can range from mildly troublesome to a life-threatening anaphylactic reaction.

Since ancient times, cats have been adored and revered, even treated as kings – and every cat lover knows that not much has changed in that. In fact, allergic pet parents will go to extreme lengths to find a way to live with their cats. These range from over-the-counter drugs like Claritin and Zyrtec to allergy shots (immunotherapy) and obsessive cleansing rituals that compete with your cats. It is also possible that some Build immunity or at least weaken the overactive immune response over time.

Unfortunately, every year many cats are given or given away to animal shelters due to allergies. According to According to the American Society for the Prevention of Cruelty to Animals, approximately 3.2 million cats are brought into the shelter every year – the main reason being allergies.

Now companies and scientists are trying to turn the script around by changing the cat as opposed to humans. The trend may have started with pet food giant Purina, which recently came out with Pro Plan LiveClear, which the company publishes Expectations can reduce Fel d 1 protein by 47% after three weeks. That would be 47% less misery for allergy sufferers.

The approach takes advantage of the Antibody-allergen interaction to neutralize the protein in the cat’s saliva on contact with the food before it can spread through the air. The new cuisine, released in Spring 2020, was formulated after research showed that 97% of cats who were fed a diet containing an egg product containing anti-Fel-d1 IgY antibodies had an active reduction in the protein on theirs Had fur and their skin flakes.

Companies like Indoor Biotechnologies in Virginia employ cutting-edge scientific techniques not only to reduce the amount of protein expressed, but to eliminate it completely.

The biotech company, whose main business focuses on the detection, testing and purification of allergens, is trying to remove Fel d 1 from cat cells using CRISPR gene editing.

The team began sequencing the two genes, chains 1 and 2, which code for the allergen, in 50 tissue samples provided by the SPCA from castration and castration procedures.

Early dates released in the Journal of Allergy and Clinical Immunology in February 2020, promising for the CRISPR approach.

“The best efficiency we have so far is 55% knockout of the gene, with which we were very happy. The cat cells are not easy to handle, so 55% knockout was pretty good, ”said Nicole Brackett, project leader and postdoctoral fellow at Indoor Biotechnologies.

Brackett and her team achieved these results at the DNA level using kidney epithelial cells that do not express the Fel d 1 protein. The next step will be to confirm that they can do this at the protein level in the cells where Fel d 1 is actually expressed.

The ultimate goal is not to create designer kitties, although Brackett said it can be. Instead, the company aims to develop a CRISPR-based drug to manipulate the DNA of existing cats. Allergic pet parents would see their vet to get the potential drug injected and take home a hypoallergenic cat.

With this approach, as with so much scientific advances, the question arises: is it ethical? The answer seems to lie in the role the protein plays in overall cat health and wellbeing – something that is currently unknown.

“Based on where [Fel d 1] In other words, it is believed that it plays a role in protecting the skin or that it acts like a pheromone in chemical communication between cats, ”Brackett said.

The team expanded their sequence analysis to include 24 exotic cats and produced initial results suggesting that Fel d 1 may not be necessary for the cat’s survival.

“The gene sequences don’t seem to be conserved as well over the course of evolution, which indicates whether the gene is essential or not,” said Brackett. “An essential gene, one that would be necessary for survival or viability, generally doesn’t change much in evolution, and we’re seeing a shift between the exotic and the domestic cat that suggests that these sequences may not be conserved are, and maybe the protein isn’t essential. “

According to Dr. Bruce Kornreich, director of the Cornell Feline Health Center, there are indications that uncastrated males produce more Fel d 1 than females and their neutered conspecifics. This would give credibility to the theory that the protein is primarily a mating call.

HypoPet in Zurich, Switzerland, uses another unique approach to keep humans and cats together – a vaccine for the cat itself.

The company, a research spin-off from the University of Zurich, is developing Fel-CuMV or HypoCat, in which particles of the cucumber mosaic virus are bound to a Fel d 1 protein. This agent then deceives the cat’s immune system into recognizing the protein as foreign and making antibodies to attack it.

While HypoPet has been working on the vaccine since its launch in 2014, it appears to be getting closer. In 2019 the company released A study in the Journal of Allergy and Clinical Immunology announced that it successfully elicited an immune response in 70 cats. In 2020, HypoPet released the results of a long-term clinical study in vaccinated cat owners showing a significant reduction in allergy symptoms.

Gary Jennings, CEO of HypoPet, recently teased that his company began partnering with one of the world’s leading animal health companies, and said that they hope to have the vaccine on the market within the next two to three years.