SUMMARYInterleukin-13 (IL-13) is critical for the development of allergic asthma and is involved in the activation of eosinophils within the airways. IL-13 exerts its activity on target cells via the dimeric IL-13 receptor (IL-13R), which comprises the IL-13 receptor a1-chain (IL-13Ra1) as a specific component. The aim of this study was to investigate the expression of the IL-13Ra1-chain on primary human eosinophilic granulocytes. Furthermore, it addresses the regulatory influence of cytokines on the level of surface abundance of this receptor subunit. Expression of IL-13-and IL-4-receptor subunits in purified primary human eosinophils was monitored at the messenger RNA level by reverse transcription polymerase chain reaction and at the protein level by flow cytometry. For the analysis of IL-13Ra1 surface expression, a new monoclonal antibody, which was generated using genetic immunization, was employed. Different cytokines with established activity on eosinophils were studied with regard to their influence on IL-13Ra1 in vitro by flow cytometry. Whereas IL-13 and IL-4 had inhibitory effects on IL-13Ra1 expression on eosinophils, interferon-c, tumour necrosis factor-a, and, to the largest extent, transforming growth factor-b, enhanced the expression of this receptor subunit. A positive regulatory response evoked by transforming growth factor-b and interferon-c does not prevent inhibitory effects caused by IL-13. These findings suggest a regulatory cytokine network influencing the reactivity of eosinophils to IL-13.

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Secondary school students tend to learn more about the usage of computers than the technology behind. It is a challenging task to raise a basic understanding, motivation, and interest in computer science and IT. The project doIT tries to fulfill this task by presenting experimental games which abstract common computer principles. The goal should be that students are led from the conceptual experiment to a greater insight into the actual, technological background.

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