If you’re among the 10% of people allergic to cats, you may put the blame on a protein in cat skin and saliva. Whenever cats groom themselves and shed their hair and dander, the irritating protein spreads all over the house. Due to its role in cat allergies, immunologists and scientists have been interested in the protein known as Fel d 1 for decades.
The options for prospective cat owners with allergies are currently limited. Some cat breeds considered “hypoallergenic” aren’t fully allergen-free, and allergy injections aren’t practical for many people. If they could stop cats from producing this protein, it would be possible to end the sneezing, wheezing, and sniffling finally.
From novel medications to crop production, CRISPR, the Nobel Prize-winning gene-editing technology, has created new possibilities for the future of hypoallergenic cats. CRISPR offers a wide range of uses in our daily lives. It may one day be able to resurrect extinct animals so that the beloved domestic cat would get its fair share of the technology with time.
A team of scientists from Indoor Biotechnologies (InBio), Virginia-based biotech, has successfully used CRISPR in tests to reduce human allergies to our feline pets. The researchers revealed an effective technique to inhibit the most prevalent source of cat allergies. They used CRISPR to remove the gene that instructs the body on how to produce Fel d 1. No animal was harmed during the process, so don’t worry.
Although the scientists used feline cells rather than live cats in their experiments, they believe the procedure is promising for real-life pets. A study published Monday in the CRISPR Journal claimed to have gathered evidence that CRISPR may be used to safely and successfully develop cats that emit little to no Fel d 1.
Eliminating certain genes
Martin Chapman, the CEO of Indoor Biotechnologies and a former professor of medicine and microbiology at the University of Virginia, tells OneZero, “We’ve been hypothesizing about what would happen if you could eliminate the gene from cats.” “What we’re hoping for is a genetically modified cat that doesn’t make Fel d 1 due to this.”
There’s been hope for hypoallergenic cats before. In the mid-2000s, biotech company Allerca claimed to sell hypoallergenic cats bred to produce less Fel d 1. But a 2013 ABC News report revealed that the cats — which cost between $4,000 to $28,000 — had similar protein levels as normal cats. One woman, who spent thousands of dollars on Allerca cats, told ABC News her children were so allergic to them that she had to give the cats away.
Unlike Allerca, Indoor Biotechnologies says it’s not interested in breeding new, genetically modified cats. Instead, the researchers’ goal in the next five years is to develop a CRISPR-based drug that will allow them to create a genetically-edited cat to help people with allergies. If the drug proves safe, pet owners suffering from pet allergies could bring their cat to the vet’s office for injection and leave with a cat that won’t cause allergies. Similarly, they will be able to enjoy a kitten hug in the future without having symptoms like red eyes and a runny nose.
The experiment
Bartz/Stockmar – Agrifood Atlas, 2017 by Bartz/Stockmar – Agrifood Atlas, 2017. Licensed under CC BY-SA 4.0
Indoor Biotechnologies collaborated with a local arm of the Society for the Prevention of Cruelty to Animals to gather tissue samples from 50 domestic cats in the quest for genes appropriate for CRISPR editing. Nicole Brackett, a postdoctoral scientist at the company, examined the extracted DNA from those 50 samples and found regions along with two genes primarily involved in creating Fel d 1.
She was looking for similarities in the gene across all 50 cats in hopes of finding a good section of DNA to target with CRISPR. The genes of these cats were then compared to those of eight wild cat species. They detected a lot of variation amongst the groups, showing that Fel d 1 isn’t necessary for cat biology and can be deleted without creating any health issues.
For a CRISPR drug to work, it would need to target a genetic sequence that appears in most cats. Finally, the researchers used CRISPR on cat cells in the lab, which seemed to be effective at knocking off Fel d 1 while causing no off-target changes in the areas where they expected modifications.
Zeroing in on a particular genetic sequence, Brackett built a CRISPR system to target it. CRISPR consists of a cutting protein and a guide molecule, which can be programmed to find any part of the genome. Once it gets there, the cutting protein does its job, slicing out that specific genetic sequence.
The research is the first step toward a CRISPR-based therapy for cats, and Indoor Biotechnologies has filed a patent for the approach. Next, the company plans to edit out the gene in cat tissues in the lab to observe whether it stops producing the allergy-causing protein.
According to the findings, “Fel d1 is “both a rational and viable choice for gene deletion, which may dramatically benefit cat allergy sufferers by removing the primary allergen at the source.”
A variety of factors causes cat allergies
Pet sensitivity is more prevalent than you would believe: It’s usually the second most common allergy in any location, according to Nature. Up to 30% of people in some areas are allergic to cats. While some people’s symptoms are only sneezing, others aren’t so fortunate, as the allergy can cause severe asthma attacks.
To put it in context, cat exposure is responsible for 47 percent of emergency hospital admissions among cat-sensitive persons. This was based on research done in the United States. Allergies are often linked to the fur and dander that cats shed, but this isn’t the root of the problem.
Over 90 percent of cat allergies are assumed to be caused by Fel d 1, a protein generated by cats that end up in their saliva and tears and, by extension, the fur they’re continuously washing. Over the years, researchers have been focusing on this protein, with the idea of using biotechnology to make cats hypoallergenic gaining traction. InBio scientists have been working on developing strategies to achieve just that.
Creating the truly hypoallergenic cat
This isn’t the only study seeking for a technique to make kittens that don’t make you sneeze. Though the early results are promising, it’s possible that the Fel d 1 protein serves some essential function other than producing allergens and that deleting it could have harmful effects on the cat. Martin and Brackett have considered that possibility, and they say the only way to find out will be to do experiments on actual cats. One approach would be to delete the protein-producing gene in cat embryos, transfer the embryos to the womb of a female cat, and see if the resulting kittens are born with any medical problems.
Others are working on less invasive approaches
Pet food companies are working on a vaccine for cats that trains their immune systems to restrict protein levels. Other researchers focus on a vaccine that trains their immune systems to reduce protein levels in their saliva. However, it does not completely eradicate the allergy. Since cats are infamous for their shedding, reducing the quantity of Fel d 1 produced by them may not be sensible in the long run.
Smaller saliva proteins may gather dust in the home, posing a major allergy risk in the long run. According to the researchers, “we may finally be able to make entirely hypoallergenic cats by treating Fel d 1 at its source with gene editing.”
The technique is still in its early stage, and the next step for the scientists will be to further refine and test their approach – first in the lab and then in real-life cats. If all goes as planned with hopefully no negative consequences, the next step will be to develop a means to engineer adult cats safely genetically.
Hope for the future
CRISPR could eliminate nearly all cat allergies if it works and doesn’t have significant side effects for our feline friends. If you’re allergic to cats, though, you shouldn’t go out and purchase one right now in the hopes of curing your allergies. A CRISPR fix is still likely several years away.
Although, according to some studies, money does buy you some degree of happiness, for cat allergy sufferers getting a cute (hypoallergenic) cat will be priceless…
