Isolation and molecular cloning of a secreted hookworm platelet inhibitor from adult Ancylostoma caninum
Isolation and molecular cloning of a secreted hookworm platelet inhibitor from adult Ancylostoma caninum
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DOI：
10.1016/s0166-6851(03)00121-x
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发表时间：
2003-07-01
影响因子：
1.5
通讯作者：
Cappello, M
中科院分区：
文献类型：
--
作者：
Del Valle, A;Jones, BF;Cappello, M
钩虫是一种吸食血液的肠道线虫，是发展中国家缺铁性贫血的主要原因。这些寄生虫进化出了干扰哺乳动物止血的有效机制，大概是为了促进血液喂养。犬钩虫成虫提取物通过阻断两种细胞表面整合素受体--糖蛋白IIb/IIIa和GPIa/IIa的功能而抑制血小板聚集和黏附。用rpHplc从犬钩虫蛋白提取物中纯化钩虫血小板抑制活性。由于通过多个层析步骤共纯化的这两种抑制活性具有相似的分子质量，并且具有相同的N末端和内部氨基酸序列同源性，因此它们很可能代表单个基因产物。从犬钩虫成虫RNA中克隆到与纯化的钩虫血小板抑制蛋白(HPI)相对应的基因，其翻译的氨基酸序列与中性粒细胞抑制因子和钩虫分泌蛋白具有显著的同源性，表明这些相关钩虫蛋白代表了一类新的整合素受体拮抗剂。针对重组HPI蛋白的多克隆抗体识别犬钩虫提取物和排泄/分泌产物中相应的天然蛋白，免疫组织化学数据表明，头腺是成虫体内抑制物的主要来源。这些数据表明，HPI是由成虫在肠道附着部位分泌的。因此，对于以疫苗为基础的策略来说，它可能是一个可行的目标，旨在干预钩虫引起的胃肠道出血和缺铁性贫血。(C)2003爱思唯尔B.V.保留所有权利。
Hookworms, bloodfeeding intestinal nematodes, are a leading cause of iron deficiency anemia in the developing world. These parasites have evolved potent mechanisms of interfering with mammalian hemostasis, presumably for the purpose of facilitating bloodfeeding. Adult Ancylostoma caninum worm extracts contain an activity that inhibits platelet aggregation and adhesion by blocking the function of two cell surface integrin receptors, Glycoprotein IIb/IIIa and GPIa/IIa. Using rpHPLC, the hookworm platelet inhibitor activities have been purified from protein extracts of A. caninum. Because the two inhibitory activities co-purified through multiple chromatographic steps, have similar molecular masses and share identical N-terminal as well as internal amino acid sequence homology, it is likely that they represent a single gene product. A cDNA corresponding to the purified hookworm platelet inhibitor (HPI) protein has been cloned from adult A. caninum RNA, and the translated amino acid sequence shows significant homology to Neutrophil Inhibitory Factor and Ancylostoma Secreted Proteins, suggesting that these related hookworm proteins represent a novel class of integrin receptor antagonists. Polyclonal antibodies raised against the recombinant HPI protein recognize corresponding native proteins in A. caninum extracts and excretory/secretory products, and immunohistochemistry data have identified the cephalic glands as the major source of the inhibitor within the adult hookworm. These data suggest that HPI is secreted by the adult stage of the parasite at the site of intestinal attachment. As such, it may represent a viable target for a vaccine-based strategy aimed at interfering with hookworm-induced gastrointestinal hemorrhage and iron deficiency anemia. (C) 2003 Elsevier B.V. All rights reserved.