Fernvik E, Lundahl J, Halldén G
Department of Laboratory Medicine, Karolinska Hospital and Institute, Stockholm, Sweden.
Inflammation. 2000 Feb;24(1):73-87. doi: 10.1023/a:1006940109869.
Eosinophils accumulate at sites of allergic inflammation, and play important roles in asthma/allergic disorders. The mechanism of eosinophil recruitment into tissues is not fully understood. In this study, we evaluated whether adhesion and/or transmigration, in the presence of IL-5 and eotaxin, alter the expression of CD9, CD11b, the beta1alpha4-integrin, and the EG2-epitope on intracellular ECP. We also investigated whether CD9 is involved in the adhesion process. With flow cytometry the surface expression of CD9, CD11b and the beta1alpha4-integrin, and the intracellular expression of EG2, were analyzed before, and after transmigration/adhesion to fibronectin. To evaluate the eventual role of CD9 in adhesion, eosinophils were preincubated with monoclonal antibodies to CD9. We observed decreased expression of CD9, and increased expression of CD11b on eosinophils, after adhesion and transmigration. The transmigration did not change the expression of the beta1alpha4-integrin or EG2, whereas the adhesion resulted in a decreased EG2 expression. Antibodies to CD9 decreased the adhesion property of eosinophils. The eosinophils are activated after both adhesion and transmigration by means of decreased CD9 and increased CD11b expression. The expression of the EG2-epitope on intracellular ECP was decreased when eosinophils adhered to fibronectin, probably due to degranulation. Our results also indicate that CD9 is involved in the adhesion of eosinophils to fibronectin.
嗜酸性粒细胞在过敏性炎症部位积聚，并在哮喘/过敏性疾病中发挥重要作用。嗜酸性粒细胞募集到组织中的机制尚未完全了解。在本研究中，我们评估了在白细胞介素-5（IL-5）和嗜酸性粒细胞趋化因子存在的情况下，黏附和/或迁移是否会改变细胞内嗜酸性粒细胞阳离子蛋白（ECP）上CD9、CD11b、β1α4整合素和EG2表位的表达。我们还研究了CD9是否参与黏附过程。通过流式细胞术分析了嗜酸性粒细胞在迁移/黏附于纤连蛋白之前和之后CD9、CD11b和β1α4整合素的表面表达以及EG2的细胞内表达。为了评估CD9在黏附中的最终作用，将嗜酸性粒细胞与抗CD9单克隆抗体进行预孵育。我们观察到，在黏附和迁移后，嗜酸性粒细胞上CD9的表达降低，CD11b的表达增加。迁移并未改变β1α4整合素或EG2的表达，而黏附则导致EG2表达降低。抗CD9抗体降低了嗜酸性粒细胞的黏附特性。通过降低CD9表达和增加CD11b表达，嗜酸性粒细胞在黏附和迁移后均被激活。当嗜酸性粒细胞黏附于纤连蛋白时，细胞内ECP上EG2表位的表达降低，这可能是由于脱颗粒所致。我们的结果还表明，CD9参与嗜酸性粒细胞与纤连蛋白的黏附。
