- Paper Report
- Open Access
Production of IL-4 by lung basophils
- Andrea Heinzmann1
© Biomed Central Ltd 2001
- Received: 13 September 2001
- Published: 13 September 2001
- Allergen challenge, asthma, IL-4, lung basophils Allergen challenge, asthma, IL-4, lung basophils
Th2 cytokines, in particular interleukin (IL)-4, IL-5 and IL-13, play an important role in the pathogenesis of asthma and other allergic diseases. The expression of these cytokines by inflammatory cells is upregulated in sites of allergic inflammation. It has long been thought that IL-4 is derived solely from T lymphocytes; however, more recent studies have demonstrated that basophils account for most of the IL-4 production in peripheral blood leucocytes. The authors of this study investigated whether, and under what conditions, basophils isolated from the lung following segmental allergen challenge secrete IL-4 in vitro.
The highest levels of IL-4 protein (after incubation under varying conditions) were detected in basophil-enriched fractions. IL-4 was not detected in any of the eosinophil preparations. Only a small amount of histamine was released by basophils under the same conditions. In contrast, high levels of histamine were obtained after stimulation with a bacterial peptide, suggesting that the cells were functional but desensitized to cross-linking stimuli as a result of their activation in vivo. As previously reported for basophils purified from blood, ionomycin enhanced the production of IL-4 by lung basophils, and addition of phorbol myristate acetate reduced this response. In contrast, a combination of both stimuli was necessary for optimal IL-4 production in mononuclear cell fractions. The secretion of IL-4 by BAL basophils was further confirmed by flow cytometry.
Segmental allergen challenge, BAL, ELISA, cell culture, flow cytometry