Chihara J, Nakajima S
Fourth Department of Internal Medicine, Kinki University School of Medicine, Osaka, Japan.
Nihon Kyobu Shikkan Gakkai Zasshi. 1992 Dec;30 Suppl:70-6.
Interleukin-5 (IL-5) acts on eosinophil differentiation and activation, suggesting the existence of a membrane receptor for IL-5 on eosinophils. Here, we report that 125I-labeled recombinant human IL-5 bound to high affinity receptors on human eosinophils, especially pulmonary eosinophils in eosinophilic pneumonia obtained bronchoalveolar lavage (BAL). No specific binding occurred on neutrophils, nor on the undifferentiated eosinophilic cell line. EoL-3, in the absence of stimulation. The specific binding of IL-5 was induced by incubation at 37 degrees C of human eosinophils and EoL-3 cells with GM-CSF and with the supernatants of BAL cells from patients with eosinophilic pneumonia. These results indicate the existence of a specific binding site for IL-5 on human eosinophils with variable affinity in eosinophil hypodense or normodense subpopulations, as previously reported for other membrane receptors. Furthermore, lung cells (BAL cells) in patients with eosinophilic pneumonia may be involved in the production certain eosinophilopoietic growth cytokines such as IL-3, GM-CSF and IL-5.
白细胞介素-5（IL-5）作用于嗜酸性粒细胞的分化和激活，提示嗜酸性粒细胞上存在IL-5的膜受体。在此，我们报告125I标记的重组人IL-5与人嗜酸性粒细胞，尤其是嗜酸性肺炎患者支气管肺泡灌洗（BAL）获得的肺嗜酸性粒细胞上的高亲和力受体结合。在中性粒细胞以及未分化的嗜酸性细胞系EoL-3在无刺激情况下均未出现特异性结合。人嗜酸性粒细胞和EoL-3细胞与粒细胞-巨噬细胞集落刺激因子（GM-CSF）以及嗜酸性肺炎患者BAL细胞的上清液在37℃孵育可诱导IL-5的特异性结合。这些结果表明，如先前报道的其他膜受体一样，人嗜酸性粒细胞上存在IL-5的特异性结合位点，在嗜酸性粒细胞低密度或正常密度亚群中具有可变亲和力。此外，嗜酸性肺炎患者的肺细胞（BAL细胞）可能参与某些嗜酸性粒细胞生成生长细胞因子如IL-3、GM-CSF和IL-5的产生。
