Purina’s Pro Plan Live Clear diet may reduce the availability and effects of a feline protein called “FEL d1” that causes cat-allergic reactions in people. Estimates say up to 10 to 30% of humans may be allergic to cats.
Fel d1 is found in cat saliva (and tears), so when cats groom their coats, they spread this allergen all over their coat. When you pet or hold your cat, you are exposed to that protein. The Purina diet uses antibodies produced in chicken eggs and then sprayed on food to reduce Fel d1 by as much as 47% after feeding it for three weeks. Studies have shown that Fel d1 does not serve any useful purpose for cats, so reducing its production should not be harmful.
In additional research, Saiba Animal Health in Switzerland has developed a vaccine for cats called HypoCat that uses recombinant Fel d1 to stimulate a cat’s own antibodies against Fel d1. Saiba reports that more than 80% of cat-allergic humans have potent allergy-inducing IgE antibodies against this protein. The vaccine utilizes a plant virus as a coating to help. The company would like to have this vaccine available in the United States by 2024. At this time, it appears that cats would need boosters every six months.
Meanwhile, Nicole Brackett, a postdoctoral scientist at Indoor Biotechnologies in Virginia, is looking at removing the Fel d1 genes in feline tissues (specifically the salivary glands to prevent a cat from spreading the protein while licking while grooming). Theoretically, gene editing could lead to feline embryos without Fel d1.