Allergy-free cats? A new CRISPR method might have the answers

From novel medicines to crop development, the Nobel Prize-winning gene-editing tech CRISPR has made its way into a plethora of applications in our lives. It could even resurrect extinct species one day, so it was just a matter of time before the beloved domestic cat received its fair share of the technology.

A team of researchers from the Virginia-based biotech company InBio has employed CRISPR in studies targeted to reduce human allergies to our feline companions, successfully uncovering an effective way to inhibit the most common source of cat allergies.

In the next five years, the researchers hope to create a gene-edited cat that'll alleviate the symptoms of people suffering from allergies. This means that, if you're one of those suffering from pet allergies —who actually make up roughly 20 percent of the world's population—, you'll be able to enjoy the hug of a kitten without experiencing symptoms like red eyes and runny nose in the future.

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The major source of cat allergies

Sensitivity to pets is more common than you might think: According to Nature, it's typically the second most prevalent allergy in any region. In fact, in some areas, up to 30 percent of people are allergic to cats.

While the symptoms can be limited to sneezes for some people, others aren't quite lucky as they can get deadly asthma attacks as a result of the allergy. To put things into perspective, according to a study conducted in the United States, cat exposure is responsible for 47 percent of emergency hospital admissions among cat-sensitive people.

Allergies are commonly connected with the fur and dander that cats shed, although this isn't the underlying cause. More than 90 percent of cat allergies are thought to be caused by Fel d 1, a protein generated by cats that ends up in their saliva and tears and, by extension, the fur that they're continuously washing. Scientists have been targeting this protein over the years, with the topic of making cats hypoallergenic with biotechnology gaining momentum.

To do just that, researchers at the InBio have been developing their own technique. In the study published Monday in the CRISPR Journal, the researchers state that they've collected evidence that CRISPR can be used to produce cats that make little to no Fel d 1 in a safe and effective manner.

In search for genes suitable for editing with CRISPR, the researchers examined the DNA of 50 domestic cats and identified regions along two genes that are predominantly involved in the production of Fel d 1. The researchers then compared the genes of these cats to those of eight wild cat species and discovered that there was a great deal of diversity across the groups, implying that Fel d 1 is not required for cat biology and can thus be removed without causing any health problems.

Finally, the researchers utilized CRISPR on cat cells in the lab, which looked to be effective at knocking off Fel d 1 and produced no off-target alterations in the places where they thought edits would most likely occur.

Based on these findings, the researchers think that Fel d1 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.”

Creating the truly hypoallergenic cat

This is not the only study looking to find a way to create less sneeze-inducing kittens. Pet food companies are developing food that inhibits the Fel d 1 in the cat's mouth, while other studies have been focusing on a vaccine for cats that trains their immune system to limit levels of the protein.

However, lowering the amount of Fel d 1 produced by cats may not be logical in the long run, as they are notorious for their excessive shedding of fur. Smaller levels of the protein may collect in house dust, posing a significant allergy risk over time. The researchers argue that, by addressing Fel d 1 at its source with gene editing, we may be able to finally create fully hypoallergenic cats.

The concept is in its early stages, and the next step for the researchers will be further refining and testing their technique, first in the lab and then in real-life cats genetically engineered cats. If all goes as planned with hopefully no negative consequences, the next step will be to develop a means to safely genetically engineer adult cats.