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Important cell group for local immune reactions discovered


Kiel team from the Cluster of Excellence "Inflammation at Interfaces" has identified a previously unknown source for the cytokine Interleukin 9

Interleukin 9 (IL-9) is one of the immune system’s soluble mediators with diverse effects. It plays a role in allergic reactions, the permeability of epithelial cells, and the anti-tumour activities of the immune system. By studying in-vitro cell cultures, a working group from the Cluster of Excellence “Inflammation at Interfaces” from the Faculty of Medicine at Kiel University (CAU) has discovered new conditions under which IL-9 is produced in significant quantities. The team, under the leadership of Prof. Dieter Kabelitz (Institute of Immunology), identified a previously unknown source for IL-9 production in the study, the so-called gamma/delta T cells (lymphocytes). In tissues such as the intestines or bronchial mucosa, for example, this type of cell is dominant. “In this regard, cytokines, which are produced in tissues by these cells, can play a major role in local inflammatory reactions,” explained Kabelitz. The results of this study have just been published in the renowned journal Proceedings of the National Academy of Sciences of the United States (PNAS).

The Kiel-based immunologist Prof. Dieter Kabelitz has been researching gamma/delta T cells (γδ T cells) for many years. These cells may only represent a small minority in the blood, but in intestinal tissues, however, they make up 20 to 30 percent of all immune cells. They are also present elsewhere in the body, such as in lung tissue, for example. His interest in these cells is primarily based on the discovery that γδ T cells ‘sense’ when other cells are stressed and there is consequently something wrong with the metabolism, which then initiates an appropriate response from the gd immune cells. They therefore play a major role in local immunomonitoring for inflammation, infection and malignant (cancerous) degeneration of cells.

In this regard, the production of Interleukin 9 (IL-9) could be clinically relevant. This cytokine can stimulate the growth of immune cells and also regulate the permeability of epithelial cells. In addition, IL-9 stimulates the production of class IgE antibodies, which play a significant role in allergic reactions and defence against parasites (worms). Furthermore, IL-9 boosts the activity of killer cells, which are important in the immunological defence against tumours, for example.

Until now, only a sub-group of the CD4+ T lymphocytes (known as CD4 cells) were known to be IL-9-producing cells in the immune system. The requirement for the release of IL-9 is activation by the cytokines Transforming Growth Factor-beta (TGFβ) and Interleukin 4. “We have shown that gamma/delta T cells also produce IL-9, and much more so than CD4 cells,” said Kabelitz. Also, with γδ T cells, only stimulation with TGFβ is necessary for producing IL-9. “The required TGFβ is produced by epithelial cells and by many tumour cells. It is therefore conceivable – in inflamed tissue, and also in a tumour micro-environment – that IL-9 is directly induced by TGFβ in the gamma/delta T cells which are present there. In this way, the local immune reaction can be influenced decisively.” Further studies plan to test the results obtained using laboratory tissue cultures in analyzing real-world diseases.

The study was funded by the Cluster of Excellence “Inflammation at Interfaces”, the Else Kröner-Fresenius Foundation and the Faculty of Medicine at Kiel University.


Original publication:

Christian Peters, Robert Häsler, Daniela Wesch, Dieter Kabelitz: Human Vδ2 T cells are a major source of Interleukin-9. PNAS 2016;




Prof. Dr. Dieter Kabelitz
The Institute of Immunology
Tel.: +49 (0)431 500 31000
Dr. Christian Peters
The Institute of Immunology
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Cluster of Excellence "Inflammation at Interfaces"
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Press and Communications, Sonja Petermann, Text: Kerstin Nees
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The Cluster of Excellence "Inflammation at Interfaces" has been funded since 2007 by the Excellence Initiative of the German Government and the federal states with a total budget of 68 million Euros. It is currently in its second phase of funding. Around 300 cluster members are spread across the four locations: Kiel (Kiel University, University Medical Center Schleswig-Holstein (UKSH)), Lübeck (University of Lübeck, UKSH), Plön (Max Planck Institute for Evolutionary Biology) and Borstel (Research Center Borstel (FZB) – Center for Medicine and Biosciences) and are researching an innovative, systematic approach to the phenomenon of inflammation, which can affect all barrier organs such as the intestines, lungs and skin.

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