Allergies begin when a type of antibody known as Immunoglobulin E recognizes a so-called allergen-a peanut protein, for example-and binds to it.
To bolster this hypothesis, a group of scientists led by computational biologist Nicholas Furnham at the London School of Hygiene & Tropical Medicine looked for similarities among 2712 proteins known to cause allergies and more than 70,000 proteins from 31 species of parasites.
Using computer programs that compared the protein sequences as well as their 3D structures, the researchers identified a list of 2445 parasite proteins that are very similar to allergenic proteins.
They found a protein in the worm Schistosoma mansoni that closely resembles one in birch pollen that makes people sneeze. It is “The first example of a plant pollen-like protein in a worm that is targeted by IgE,” the researchers write today in PLOS Computational Biology. Some examples of allergens resembling worm proteins were already known, she says, but this is the first systematic look.
Knowing what parasite protein the allergen resembles could allow doctors to give that protein to patients instead of the pollen; that would make it easier to dose the allergy shots, as well as make the immunotherapy safer, Furnham says.