Abstract

The classical allergic reaction starts within seconds or minutes after antigen contact and is induced by antibodies produced by a special subset of B lymphocytes. These antibodies belong to the IgE subclass and are responsible for Type I hyper-reactivity reactions. IgE plays a minor role in healthy individuals. In allergic individuals, however, IgE antibodies trigger allergic responses through allergen-mediated cross-linking on effector cells followed by mediator release. The mechanisms inducing a switch to IgE production are not fully understood with the consequence that allergies are mainly treated with antisymptomatic drugs. To develop basic therapies, many questions concerning the very complex regulation of IgE expression have to be understood. Positive and negative regulators influence the synthesis of IgE. Experiments in our laboratory could show that not only regulatory molecules, but also the membrane bound IgE itself controls the quantity and quality of the IgE produced. This fact becomes more and more interesting, because the signals generated by the B-cell receptor may be important targets for interference in allergic patients, in whom the titer and the affinity of the IgE antibodies for the allergen are directly related to disease activity.