Fornhem C, Peterson C G, Scheynius A, Alving K
Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden.
Clin Exp Allergy. 1996 Apr;26(4):469-78. doi: 10.1111/j.1365-2222.1996.tb00564.x.
Eosinophils are associated with bronchial asthma, but the role of the eosinophil is not fully understood. This study was initiated in order to study the influence of endogenous cortisol on eosinophil recruitment and activation in allergic inflammation in the lower airways in the pig.
Polyclonal and monoclonal antibodies against porcine eosinophil peroxidase (EPO) were raised. Detection of eosinophils in blood smears and lung biopsy specimens was achieved using the polyclonal antibody. For determination of porcine EPO in bronchoalveolar lavage (BAL) fluid, a sandwich enzyme-linked immunosorbent assay (ELISA) with a detection limit of 0.15 micrograms/L was developed. No cross-reactivity with porcine myeloperoxidase was found. Pigs that had been actively sensitized with repeated subcutaneous injections of Ascaris suum antigen were acutely challenged with antigen in the lower airways under pentobarbitone anaesthesia.
Control animals with plasma cortisol levels of approximately 400 nM did not exhibit infiltration of eosinophils into lung parenchyma or EPO-release in the bronchial lumen within 8 h after challenge. However, in pigs treated with a cortisol-synthesis inhibitor (metyrapone), resulting in plasma cortisol levels of approximately 40 nM, there was a marked eosinophil infiltration into lung tissue at 8 h. Furthermore, EPO levels in BAL fluid were increased in some, although not all, low-cortisol animals. There was no infiltration of eosinophils into skin tissue in these animals.
It is concluded that, after allergen challenge in the lower airways of metyrapone-treated pigs, newly recruited eosinophils infiltrate lung tissue specifically. Furthermore, a cortisol-sensitive release of the eosinophil-derived cationic protein EPO, into the bronchial lumen was established. This is, to our knowledge, the first description of direct measurements of the release of an eosinophil granule protein in a large animal model of allergy.
嗜酸性粒细胞与支气管哮喘相关，但其作用尚未完全明确。开展本研究以探讨内源性皮质醇对猪下呼吸道变应性炎症中嗜酸性粒细胞募集与活化的影响。
制备抗猪嗜酸性粒细胞过氧化物酶（EPO）的多克隆和单克隆抗体。使用多克隆抗体检测血涂片和肺活检标本中的嗜酸性粒细胞。为测定支气管肺泡灌洗（BAL）液中的猪EPO，开发了一种检测限为0.15微克/升的夹心酶联免疫吸附测定（ELISA）法。未发现与猪髓过氧化物酶有交叉反应。对经皮下反复注射猪蛔虫抗原主动致敏的猪，在戊巴比妥麻醉下对下呼吸道进行抗原急性激发。
血浆皮质醇水平约为400纳摩尔的对照动物在激发后8小时内未出现嗜酸性粒细胞浸润到肺实质或支气管腔内EPO释放的情况。然而，在用皮质醇合成抑制剂（甲吡酮）处理的猪中，血浆皮质醇水平约为40纳摩尔，在8小时时有明显的嗜酸性粒细胞浸润到肺组织中。此外，部分（并非全部）低皮质醇动物的BAL液中EPO水平升高。这些动物的皮肤组织未出现嗜酸性粒细胞浸润。
得出结论，在甲吡酮处理的猪下呼吸道进行变应原激发后，新募集的嗜酸性粒细胞特异性浸润肺组织。此外，还证实了嗜酸性粒细胞衍生的阳离子蛋白EPO向支气管腔内的皮质醇敏感性释放。据我们所知，这是在大型变应性动物模型中首次直接测量嗜酸性粒细胞颗粒蛋白释放的描述。
