Scientists move one step closer to creating a dog allergy vaccine

SAKAI, Japan — Dog allergies keep many prospective pet owners from adopting a furry friend, but scientists are now one step closer to changing all that. Researchers from Osaka Prefecture University say they’ve identified a series of molecules that may explain why people have allergic reactions to dogs and also reveal how to cure them.

The team notes that this study pinpoints the seven molecules which make up dog allergens for the first time. With that knowledge, they believe scientists can train the human immune system to stop overreacting to specific particles which cause some people to sneeze, itch, or experience breathing problems — essentially creating a “dog allergy vaccine.”

One epitope is worse than the rest

Scientists call these seven dog allergens — molecules which bind to human antibodies and cause abnormal immune response — Canis familiaris allergens 1 to 7 (or Can f 1-7). While there may be at least seven that’ll make you sneeze, the study finds Can f 1 causes the vast majority of allergic reactions in people (50 to 75%). The team adds that dogs carry this allergen in their tongue tissue, salivary glands, and skin.

In an effort to cure people of their dog allergies, scientists started looking for Can f 1’s IgE epitopes. These are the specific parts of the antigens that a person’s immune system recognizes. They also determine how much of a response the immune system needs to prepare when encountering these particles.

When dog allergens enter the body, the epitopes bind to specific antigen receptors on the surface of the immune system’s antibodies, B cells, or T cells. Like the allergens, the body’s antibodies also have different classes: IgA (for immunoglobulin A), IgD, IgE, IgG, or IgM.

However, IgE is unique to mammals and plays a major role in the development of allergies. Like a puzzle, Can f 1’s IgE epitope fits the IgE receptor on the surface antibodies and may be the trigger for a person having dog allergies.

With that discovery, the team is hoping to develop an epitope-focused vaccine to cure people of allergic reactions to man’s best friend.

“We want to be able to present small doses of these epitopes to the immune system to train it to deal with them, similar to the principle behind any vaccine,” says Professor Takashi Inui, a specialist in allergy research and lead author of the study, in a university release. “But we can’t do this without first identifying the Can f 1’s IgE epitope.”

Finding the right piece of the puzzle will stop dog allergies

For the first time ever, the team used a technique called X-ray crystallography to determine the exact structure of the Can f 1 protein. They found the protein’s folding pattern is very similar to three other Can f allergens but Can f 1’s electrical charges are much different. This likely means that a series of “residues” the team discovered are the IgE epitope they’re looking for.

Through further studies, the team hopes to narrow down the list of candidates which could be the actual IgE epitope. From there, scientists can create a hypoallergenic vaccine that teaches the body not to overreact to Can f 1.

The study is published in the Federation of European Biochemical Societies journal.