Scientists have found a number of molecular possibilities for the portions of dog allergens that induce immunological responses in humans, which is the first step toward producing a vaccine for most dog allergy causes.
There have been numerous studies that describe the nature and evolution of dog allergies, but there have been few practical studies that utilize this knowledge to attempt to completely treat patients with dog allergies by intentionally generating immunological tolerance. But, for the first time, scientists have found possibilities for sections of the molecules that make up dog allergens that might lead to the development of a “dog allergy vaccine.”
On October 26, their results were published in the journal of the Federation of European Biochemical Societies.
Being allergic to dogs is a widespread ailment that is spreading over the globe. Scientists have identified seven distinct dog allergens throughout the years, which are chemicals or molecular structures that attach to an antibody and cause an extremely powerful immune reaction that would otherwise be innocuous.
Canis familiaris allergens 1 to 7 are the names given to these seven allergens (Can f 1-7). However, although there are seven, only one, Can f 1, is responsible for the bulk of responses in those allergic to dogs (50-75 percent). It’s present in the tissue of dogs’ tongues, salivary glands, and skin.
Can f 1’s IgE epitopes — those precise sections of antigens that are recognized by the immune system and trigger or ‘determine’ an immunological response — have yet to be identified (which is why epitopes are also called antigen determinants). Epitopes are short amino acid sequences that make up a portion of a protein that triggers an immunological response.
Epitopes attach to a particular antigen receptor on the surface of immune system antibodies, B cells, and T cells, similar to how a jigsaw puzzle piece fits into the exact form of another puzzle piece. (A paratope is the portion of the receptor that binds to the epitope.) Antibodies, also known as immunoglobulins, are divided into five categories or isotypes: IgA (immunoglobulin A), IgD, IgE, IgG, and IgM. In allergies and allergic disorders, the IgE isotype (present exclusively in animals) plays a critical role. There’s also an IgE epitope that matches the IgE isotype’s paratope like a jigsaw piece.
In recent years, a lot of research has gone into producing epitope-focused vaccinations, such as this one for dog allergies.
“We hope to be able to provide modest doses of these epitopes to the immune system to educate it to cope with them, similar to the premise underlying any vaccination,” Takashi Inui, an allergy researcher and professor at Osaka Prefecture University, said. “However, we can’t accomplish this without first finding the IgE epitope of Can f 1.”
As a result, the researchers utilized X-ray crystallography (the analysis of x-ray diffraction through a substance to discover its ‘crystal’ structure) to determine the structure of the Can f 1 protein as a whole, which was the first time this had ever been done.
They discovered that the protein’s folding pattern is very similar to those of three known Can f allergens. The positions of surface electrical charges, on the other hand, were considerably diverse, suggesting a succession of’residues’ that might be potential candidates for the IgE epitope.
More experimental work is needed to narrow down the choices using this basic data, but the results imply that developing a hypoallergenic vaccination against Can f 1 — a dog-allergy vaccine — is within reach.
The development of a ‘hypoallergenic vaccination’ using such epitopes would not only be a global first for dog allergies, but it would also be very unlikely for any allergic response. The concepts underpinning the researchers’ work might be utilized much more generally against other allergies if their work is used to build a dog allergy vaccine.