Investigators at the National Institute of Allergy and Infectious Diseases, or NIAID, have uncovered information suggesting a new explanation for why some people are allergic to allergens. The research team found that differences in the structure of the foreign proteins made them allergenic.
Food allergies, asthma, and seasonal allergies affect millions of people. Many allergic diseases seem to be affecting more people than in previous decades. The allergens behind these reactions come from many different sources, including food, pets, and grass.
Researchers already knew that certain proteins in the allergy-causing substance interact with the immune system, provoking a response. Exactly what makes these proteins allergenic is not well understood.
One hypothesis is that when an environmental protein is similar to one found in people or microbes, the more likely it will prompt an allergic reaction. According to this hypothesis, allergies to pet dander result because the structure of pet proteins is similar to the structure of proteins found in humans.
Research Team Finds Different Explanation For Allergies
The NIAID research team set out to prove this hypothesis. However, they found a much different explanation for why some proteins cause allergic reactions. They searched a database of nearly 500 known allergens, looking for similarities in the genetic structure between the protein and the proteins of bacteria, fungi, protozoans, and parasitic worms.
They found that many of the allergens were significantly similar to other proteins. However, they found that allergens which were structurally dissimilar to microbes prompted the bodies of allergic people to produce more immunoglobulin E (IgE), the major antibody involved in an allergic reaction. As a result, the researchers concluded that structurally dissimilar proteins actually caused a stronger allergic reaction.
The finding suggest that differences in structure between foreign proteins and human or microbial proteins determine whether or not it is likely to prompt an allergic reaction.