Hamann K J, Gleich G J, Checkel J L, Loegering D A, McCall J W, Barker R L
Department of Immunology, Mayo Medical School, Rochester, MN 55905.
J Immunol. 1990 Apr 15;144(8):3166-73.
Eosinophil infiltration and degranulation around the tissue-invasive stages of several species of helminths have been observed. Release of eosinophil granule contents upon the worms is supported by localization of two of the major granule proteins, major basic protein (MBP) and eosinophil peroxidase (EPO), on and around species of trematodes, nematodes, and cestodes. In the case of filarial worms, MBP is deposited on degenerating microfilariae (mf) of Onchocerca volvulus. Here, we performed in vitro assays of the toxicity of four purified eosinophil granule proteins, namely, MBP, EPO, eosinophil cationic protein (ECP), and eosinophil-derived neurotoxin (EDN), for the mf of Brugia pahangi and Brugia malayi. MBP, ECP, and EDN killed these worms in a dose-related manner although relatively high concentrations of EDN were necessary. EPO, in the presence of a H2O2-generating system and a halide, was the most potent toxin on a molar basis; here, the most potent halide was I- followed by Br- and Cl-. Surprisingly, EPO in the absence of H2O2 killed mf at concentrations comparable to those required for MBP and ECP. The toxicity of EPO + H2O2 + halide was inhibited by heparin, catalase, or 1% BSA, whereas the toxicity of EPO alone was inhibited only by heparin. Heparin also inhibited killing by both MBP and ECP. Despite the homology of ECP with certain RNases, placental RNasin, an RNase inhibitor, was unable to inhibit ECP-mediated toxicity. These results indicate that all of the eosinophil granule proteins are toxic to mf and they support the hypothesis that eosinophil degranulation causes death of mf in vivo.
在几种蠕虫的组织侵袭阶段周围，已观察到嗜酸性粒细胞浸润和脱颗粒现象。两种主要颗粒蛋白，即主要碱性蛋白（MBP）和嗜酸性粒细胞过氧化物酶（EPO），定位于吸虫、线虫和绦虫物种及其周围，这支持了嗜酸性粒细胞颗粒内容物释放到蠕虫上的观点。就丝虫而言，MBP沉积在盘尾丝虫退化的微丝蚴（mf）上。在此，我们对四种纯化的嗜酸性粒细胞颗粒蛋白，即MBP、EPO、嗜酸性粒细胞阳离子蛋白（ECP）和嗜酸性粒细胞衍生神经毒素（EDN），进行了对彭亨布鲁线虫和马来布鲁线虫mf的体外毒性测定。MBP、ECP和EDN以剂量相关的方式杀死这些蠕虫，尽管需要相对较高浓度的EDN。在存在产H2O2系统和卤化物的情况下，EPO按摩尔计算是最有效的毒素；在此，最有效的卤化物是I-，其次是Br-和Cl-。令人惊讶的是，在不存在H2O2的情况下，EPO在与MBP和ECP所需浓度相当的浓度下杀死mf。EPO + H2O2 + 卤化物的毒性被肝素、过氧化氢酶或1%牛血清白蛋白抑制，而单独EPO的毒性仅被肝素抑制。肝素也抑制MBP和ECP的杀伤作用。尽管ECP与某些核糖核酸酶具有同源性，但胎盘核糖核酸酶抑制剂核糖核酸酶抑制剂无法抑制ECP介导的毒性。这些结果表明，所有嗜酸性粒细胞颗粒蛋白对mf都有毒性，并且支持嗜酸性粒细胞脱颗粒导致体内mf死亡的假说。
