Allergies in humans and animals are on the increase. An allergic reaction may cause unpleasant symptoms like hay fever, food intolerance or skin rashes. Allergic reactions may also cause acute and life-threatening symptoms, such as asthma or anaphylactic shock.
A single pollen protein is responsible for allergies
One of the most well known allergens, i.e. substances that cause allergies, is so-called "Bet v 1" from birch pollen (Betula verrucosa). The protein was first produced artificially in the laboratory 25 years ago in Vienna, and is being used as an allergen model for research throughout the world. "Bet v 1" is the principal allergen among hundreds of other proteins of birch pollen. It renders the immune system hypersensitive and leads to the formation of disease-causing antibodies known as IgE immunoglobulins in 95 percent of persons with a pollen allergy.
Birch pollen protein in its iron-loaded state is not allergenic
Until recently it was not known why harmless molecules trigger allergies at all. Scientist Franziska Roth-Walter and her colleagues from the Messerli Research Institute have now found the possible cause. The birch pollen protein "Bet v 1" is very similar to the human protein Lipocalin 2 in terms of structure; Lipocalin 2 is mainly present in the lung. Lipocalin 2 and "Bet v 1" possess so-called molecular pockets with which they can bind iron. When these pockets remain empty, the birch pollen protein becomes an allergen and is liable to cause allergic reactions in humans and animals. The protein manipulates so-called T-helper 2 cells (Th2 cells), a certain type of immune cells, towards allergy. The human protein Lipocalin 2 also performs tasks of the immune system, depending on its iron loading.
Origin of allergy investigated in the model of birch pollen
In allergic people and other mammals, Th2 cells are predominant compared to Th1 cells. Th2 cells play an
|Contact: Erika Jensen-Jarolim|
University of Veterinary Medicine -- Vienna