Approximately 15% of the world's population lives with dog allergies, a condition that can increase the risk of allergic rhinitis and asthma. The main culprit is the Can f 1 protein, present mostly in dogs' saliva. Currently, staying away from dogs or receiving regular immunotherapy are the only options for controlling symptoms.
A recent study published in The CRISPR Journal explored whether it is possible to eliminate dog allergies by attacking the biological source of the problem directly. Rather than focusing on treating human symptoms, the researchers sought to determine whether dogs could be genetically edited to stop producing the allergen altogether. The team used CRISPR-Cas9 technique to make a small precise cut in the Can f 1 gene in dog skin cells and inserted a single additional DNA building block. This small change deactivated the gene, preventing it from producing the allergen protein. The edited DNA was introduced into mature eggs from donor beagles, resulting in two female puppies, Alfie and Bailey, born from cloned embryos.
When the researchers analysed the dogs' saliva, coat and dander, they found no detectable trace of the Can f 1 allergen protein. The biochemists performed tests on saliva, coat and dander samples from the edited dogs, a normal beagle, a standard poodle and a goldendoodle. While the protein was easily detected in the other dogs, including poodles and goldendoodles marketed as hypoallergenic breeds, it was completely absent in the edited dogs.
Then came the decisive test: determining whether the beagles caused an allergic reaction. Using a standard skin prick device, the team applied protein extracts from each dog to a volunteer's arm and observed any reaction. The volunteer developed allergic bumps after exposure to the normal beagle and even to the supposedly hypoallergenic breeds, but the genetically modified dogs provoked no reaction whatsoever.
The study demonstrates that it is technically possible to directly disable the main dog allergen in a living animal. However, before this approach can be used commercially, the researchers will need to establish its long-term safety, ensure careful oversight of animal welfare and comply with all regulatory requirements, the team noted.