How the immune system can develop tolerance to allergens
Scientists at Charité – Universitätsmedizin Berlin and the Johannes Gutenberg University in Mainz have clarified an endogenous mechanism that can prevent the development of allergies. They were able to show that certain cells of the immune system, so-called killer dendritic cells, are capable of eliminating allergy cells. The results of the study, which have now been published in the renowned Journal of Clinical Investigation*, open up new perspectives for strategies to protect against allergies.
The term allergen is used to describe a substance that is detected as being foreign on making contact with the organism and brings about excessive defense on the part of the immune system, an allergic reaction. It has been known for a long time now that in the event of repeated contact with a very low dose of an allergen the body can develop a kind of immunity to it. This process is referred to as "low zone tolerance." The exact mechanisms on which this immunity is based are still largely unknown. The present study was able to decipher important cellular mechanisms for the first time using a mouse model. The results were obtained in close collaboration between the Mainz research team led by Prof. Kerstin Steinbrink and the research team led by Prof. Marcus Maurer from the Charité Allergy Center. Killer dendritic cells, which are also described as the sanitary police, release a certain semiochemical on making contact with an allergen. In cells that facilitate the allergic reaction this so-called tumor necrosis factor triggers programmed cell death, apoptosis. As a result, it is not possible for an allergic reaction to develop. The very different personal degrees of ability to develop this "low zone tolerance" are probably also the reason why some individuals react to certain allergens and others do not.
"The results of the study are basically of relevance to everyone," says Prof. Maurer. "Especially people who have greater contact with allergenic substances run the risk of developing an allergy some day." They include, for example, people employed in hair salons and in the jewelry and fashion industries, but also hospital staff. "In our research paper we identified the mechanism on which the prevention of an allergy is based," Prof. Maurer explains. The dermatologist and allergist assumes that the results can in future be used in therapy and therefore to avoid allergies.
*Luckey et al.: T cell killing by tolerogenic dendritic cells protects from allergy in mice. Journal of Clinical Investigation, October 2011. [epub ahead of print]
Prof. Marcus Maurer
Campus Charité Mitte
t: +49 30 450 518 043
Back to Overview