If 2021 was the year of mRNA vaccines, could 2022 be the year of epitope-based vaccines? Despite being a target too early, scientists at Osaka Prefecture University in Japan recently laid the essential foundation for the development of an epitope-based vaccine for canine allergy.
If the work is successful in the experimental and clinical phases, the “hypoallergenic vaccine” would not only be a world first in dogs, but would also open the door to the treatment of a wide range of allergies.
Over the years, scientists have identified seven different canine allergens, named Canis familiaris allergens 1-7 (Can f 1-7) —responsible for producing the unusually strong immune response seen in a typical allergic reaction. Today, for the first time, a team led by Takashi Inui has identified the parts of the molecules that make up allergies in dogs. This information could be used to artificially induce a person’s immune tolerance.
Although there are seven allergens, only one – Can f 1 – is responsible for 50-75% of reactions in people with allergies to dogs. But, researchers have yet to identify the IgE epitopes of Can f 1 – or the specific parts of antigens that are recognized by the immune system to stimulate an immune response.
“We want to be able to present small doses of these epitopes to the immune system to train it to handle them, just like the principle of any vaccine,” said Inui, an allergy researcher, professor. at Osaka Prefecture University and responsible. author of the study. “But we can’t do that without first identifying the Can f 1 IgE epitope.”
Using X-ray crystallography, the team was able to determine, for the first time, the structure of the Can f 1 protein as a whole. They found that at first glance, the protein’s folding pattern is extremely similar to that of three other Can f allergens. However, the locations of the surface electrical charges were different, suggesting a series of “residues” which are good candidates for the IgE epitope.
Although there are five classes of antibodies, previous research has shown that the IgE isotype, which is only found in mammals, plays a key role in allergies and allergic disease regardless of the condition. host.
“There is also an IgE epitope which is the piece of the puzzle that corresponds to the paratope of the IgE isotype,” explains the research team.
There is a long roadmap in front of researchers, the first phase being more in vivo work to refine the list of “candidate” residues.
Despite this, the findings published by Inui and his team in The Federation of European Biochemical Societies Newspaper lay the crucial foundation for the possibility of a dog allergy vaccine in the near future.