The protein that causes the majority of cat allergies can be safely erased from the feline genome, according to a new study in The CRISPR Journal. Using gene-editing technology, the researchers managed to prevent cat cells in a dish from producing the culprit molecule, and say that their approach could one day be used to make live cats hypoallergenic.
Cat allergies are predominantly caused by a protein called Fel d 1, which is secreted through the animals’ saliva and tears and ends up in their fur as they groom themselves. The irritating compound then accumulates in the homes of cat owners as the moggies shed their fur, making visits rather uncomfortable for anyone who suffers from allergies.
After analyzing the DNA of 50 domestic cats, the study authors identified regions on two genes – known as CH1 and CH2 – that code for the Fel d 1 protein. To determine whether or not these targets are suitable candidates for gene editing, they then looked at the genomes of eight different species of wild cats and found that these coding regions displayed a great deal of variation between species.
This finding implies that the genes for Fel 1 d have not been evolutionarily conserved, which suggests that the allergen is probably not essential to cat biology and can therefore be erased without harming the animals. Scientists were previously unsure if this was the case as the protein’s function is not fully understood.
According to the authors, Fel 1 d is not found in any organisms outside of the cat family, although a similar protein in mice has been genetically erased without causing any deleterious effects, reinforcing the notion that the compound is probably non-essential.
The researchers then used the gene-editing technology CRISPR to eliminate the Fel 1 d coding regions in cat cells. Doing so caused no unwanted genetic changes in any of the regions where they predicted off-target edits might be likely to occur.
“Taken together, our data indicate 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,” they write.
Alternative approaches to tackling cat allergies, they say, are likely to be ineffective since they don’t fully eliminate Fel d 1. For example, cat food products containing antibodies that destroy the protein have been shown to reduce antigen levels by 47 percent, while vaccines appear to eliminate around 50 percent of the offending substance.
However, the authors say that allergic individuals tend to experience symptoms even when exposed to tiny quantities of Fel 1 d, and that the complete eradication of the protein using gene-editing technologies may therefore be the only solution.
More research is now needed to refine the technique, though the researchers optimistically proclaim that “future studies will aim to develop a means for deleting the Fel d 1 genes in adult cats and effectively rendering the cats hypoallergenic.”
