A team of researchers say they’ve found an effective way to block the most common source of cat allergies using the gene-editing technology CRISPR. Their findings also suggest that hypoallergenic cats can be just as healthy as the typical feline.
Allergies are most associated with the fur and dander that cats shed into the environment, but those aren’t the true culprit. A protein produced by cats called Fel d 1—which ends up in their saliva and tears and, by extension, the fur that they’re constantly cleaning—is thought to cause over 90% of cat allergies. This has made the protein an appealing target for scientists trying to reduce the burden of cat allergies, which may affect up to 20% of people.
Researchers at the Virginia-based biotech company InBio (previously called Indoor Biotechnologies) have been working on their own approach. They’re hoping to use CRISPR, the Nobel Prize-winning gene editing tech, to produce cats that simply make little to no Fel d 1. In their latest research, published Monday in The CRISPR Journal, they say they’ve collected evidence that this can be done effectively and safely.
Analyzing the DNA of 50 domestic cats, they found regions along two genes primarily involved in producing Fel d 1 that would be suitable for editing with CRISPR. When they compared the genes of these cats to those from eight wild cat species, they also found that there was a lot of variation between the groups. That could indicate, as other research has suggested, that Fel d 1 is non-essential to cat biology and can thus be eliminated without any health risks. (Some cat breeds, like the Russian blue and Balinese, are often touted as being better for people with allergies because they may naturally produce less Fel d 1.) Lastly, the team used CRISPR on cat cells in the lab, which seemed to be effective at knocking out Fel d 1 and appeared to produce no off-target edits in the areas they predicted that edits would most likely happen.
All in all, the researchers say that their findings show that “Fel d 1 is both a rational and viable candidate for gene deletion, which may profoundly benefit cat allergy sufferers by removing the major allergen at the source.”
There are plenty of ongoing efforts to create less sneak-inducing cats. In early 2020, pet food company Purina released its LiveClear line of products—cat food that’s been treated with an egg-based protein that inhibits the Fel d 1 in their mouths. The company’s research has found that levels of Fel d 1 in cat fur and dander drop by an average 47% after three weeks of cats eating LiveClear. Elsewhere, other researchers have been working on a vaccine for cats that trains their immune system to reduce levels of the protein.
The authors of the new study note that modestly reducing the amount of Fel d 1 produced by cats may be possible in lots of ways. But since, as any cat owner knows, cats are constantly shedding fur, it’s still possible for smaller amounts of Fel d 1 to accumulate in house dust and pose a major allergic threat. By targeting Fel d 1 at its root using gene-editing, they argue, it may be possible to create truly hypoallergenic cats.
Of course, this is all still early days. The scientists plan to continue refining and testing out their technique, both in the lab and eventually in real-life cats genetically bred to have their Fel d 1 knocked out. Should that work out as hoped, with no adverse effects, the next step would be to find a way to safely genetically edit adult cats.