Ackerman S J, Gleich G J, Loegering D A, Richardson B A, Butterworth A E
Am J Trop Med Hyg. 1985 Jul;34(4):735-45. doi: 10.4269/ajtmh.1985.34.735.
The human eosinophil granule contains several distinctive cationic proteins that have been purified to homogeneity, including major basic protein (MBP), eosinophil cationic protein (ECP), and eosinophil-derived neurotoxin (EDN). Two earlier studies have shown that MBP and ECP both damage schistosomula of Schistosoma mansoni in vitro in a dose-dependent fashion. The present study expands upon these observations by comparing the toxicity of MBP, ECP, as well as EDN when tested at equimolar concentrations (0.03-2 X 10(-5) M). On a molar basis, ECP was 8 to 10 times more potent than MBP, and the ECP-mediated killing of schistosomula was qualitatively different than that of MBP. Purified ECP produced complete fragmentation and disruption of schistosomula, whereas MBP produced a distinctive ballooning and detachment of the tegumental membrane. In contrast, EDN was only marginally toxic at high concentrations and caused crinkling of the tegumental membrane. Heating MBP and ECP for four hr at 56 degrees C caused precipitation and loss of toxicity for MBP, but not for ECP. Native MBP (with reactive sulfhydryl groups intact) and stabilized, reduced and alkylated MBP had comparable toxicity. To determine the relative contribution of MBP, ECP and other potentially helminthotoxic eosinophil granule constituents to schistosomulum damage, fractions of acid soluble granule extracts prepared by chromatography on Sephadex G-50 columns were analyzed for toxicity to schistosomula and for MBP and ECP levels by radioimmunoassay. Schistosomula were killed by fractions containing MBP, and to a much lesser and more variable extent by fractions containing EDN and a 21,000 dalton protein, but not by fractions coincident with the elution of ECP, which contained concentrations of ECP below that required to produce significant killing of schistosomula by the purified protein. Therefore, although ECP is a more potent helminthotoxin for schistosomula than MBP on a molar basis, MBP, by virtue of its abundance in the granule, accounts for the bulk of the toxicity in fractions of acid solubilized granules obtained from eosinophils of patients with marked eosinophilia.
人类嗜酸性粒细胞颗粒含有几种已纯化至同质的独特阳离子蛋白，包括主要碱性蛋白（MBP）、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）。两项早期研究表明，MBP和ECP在体外均以剂量依赖方式损伤曼氏血吸虫的童虫。本研究通过比较等摩尔浓度（0.03 - 2×10⁻⁵ M）下MBP、ECP以及EDN的毒性，对这些观察结果进行了扩展。以摩尔为基础，ECP的效力比MBP高8至10倍，并且ECP介导的童虫杀伤在性质上与MBP不同。纯化的ECP使童虫完全破碎和解体，而MBP则导致被膜明显肿胀和脱离。相比之下，EDN在高浓度时仅具有轻微毒性，并导致被膜起皱。将MBP和ECP在56℃加热4小时会导致MBP沉淀并丧失毒性，但ECP不会。天然MBP（活性巯基完整）以及稳定化、还原和烷基化的MBP具有相当的毒性。为了确定MBP、ECP和其他潜在的抗蠕虫毒性嗜酸性粒细胞颗粒成分对童虫损伤的相对贡献，对通过Sephadex G - 50柱色谱制备的酸溶性颗粒提取物的各部分进行了分析，检测其对童虫的毒性以及通过放射免疫测定法检测MBP和ECP水平。含有MBP的部分可杀死童虫，而含有EDN和一种21,000道尔顿蛋白的部分在程度上要小得多且更具变异性，含有ECP的部分（其ECP浓度低于纯化蛋白产生显著杀伤童虫所需的浓度）则不能杀死童虫。因此，尽管在摩尔基础上，ECP对童虫而言是比MBP更有效的抗蠕虫毒素，但由于MBP在颗粒中的含量丰富，它在从嗜酸性粒细胞显著增多的患者中获得的酸溶性颗粒部分的毒性中占了大部分。
