The role of MIF in hookworm infection and disease

描述（由申请人提供）：钩虫感染是发展中国家营养不良和贫血的主要原因。超过10亿人感染了这些吸血线虫寄生虫，它们附着在肠黏膜上，从撕裂的毛细血管中取食。钩虫可以在肠道内存活数年，尽管宿主存在炎症反应。迄今为止，关于成年钩虫为了生存而阻断先天和获得性宿主免疫反应成分的机制知之甚少。最近从人钩虫中克隆出了一种与哺乳动物细胞因子巨噬细胞迁移抑制因子（MIF）同源的eDNA。初步数据表明，重组A. ceylanicum MIF （rAceMIF）具有酶活性，并与人蛋白竞争，以结合最近发现的MIF受体CD74。我们假设钩虫MIF同源物有效地调节宿主免疫反应，以促进寄生虫在粘膜表面的生存。该项目的目的是确定MIF在钩虫感染和疾病发病机制中的作用。AceMIF的作用机制将通过MIF功能的体外研究来表征，包括互变酶活性、巨噬细胞迁移和促炎细胞信号传导。将对rAceMIF与CD74结合的动力学进行表征，并利用x射线晶体学对其三维结构进行阐明。AceMIF基因在体内的表达将被表征，以记录其阶段特异性，而AceMIF在成年钩虫体内的产生来源将通过免疫组织化学来表征。平行研究将分析宿主MIF对钩虫感染反应的组织特异性表达，使用完全允许的动物模型。AceMIF在钩虫贫血和生长迟缓发病机制中的作用也将通过疫苗和靶向基因沉默方法来表征。免疫反应将通过ELISA监测，针对AceMIF的抗体对钩虫贫血和生长迟缓的保护程度将通过临床参数和蠕虫负荷测量来评估。这些研究将表征这种新的蠕虫同源物的多功能人类细胞因子，最终确定MIF在钩虫病发病机制中的作用。

DESCRIPTION (provided by the applicant): Hookworm infection is a leading cause of malnutrition and anemia in the developing world. More than one billion people are infected with these bloodfeeding nematode parasites, which attach to the intestinal mucosa and feed from lacerated capillaries. Hookworms may survive for years within the intestine, despite the presence of a host inflammatory response. To date, little is known about the mechanisms by which adult hookworms block components of the innate and acquired host immune responses in order to survive. A eDNA corresponding to a homologue of the mammalian cytokine Macrophage Migration Inhibitory Factor (MIF) has recently been cloned from the human hookworm Ancylostoma ceylanicum. Preliminary data suggest that the recombinant A. ceylanicum MIF (rAceMIF) is enzymatically active and competes with the human protein for binding to the recently identified MIF receptor CD74. We hypothesize that the hookworm MIF homologue effectively modulates the host immune response in order to facilitate parasite survival at the mucosal surface. The aim of this project is to characterize the role of MIF in the pathogenesis of hookworm infection and disease. The mechanism of action of AceMIF will be characterized using in vitro studies of MIF function, including tautomerase activity, macrophage migration, and pro-inflammatory cell signaling. The kinetics of rAceMIF binding to CD74 will be characterized, and its three dimensional structure will be elucidated using X-ray crystallography. AceMIF gene expression will be characterized in vivo in order to document its stage specificity, and the source of AceMIF production within the adult hookworm will be characterized by immunohistochemistry. Parallel studies will analyze tissue specific expression of host MIF in response to hookworm infection using a fully permissive animal model of A. ceylanicum. The role of AceMIF in the pathogenesis of hookworm anemia and growth delay will also be characterized using both vaccine and targeted gene silencing approaches. The response to immunization will be monitored by ELISA, and the degree to which antibodies directed at AceMIF protect against hookworm anemia and growth delay will be assessed using clinical parameters and worm burden measurements. These studies will characterize this novel helminth homologue of a multi functional human cytokine, ultimately determining the role of MIF in the pathogenesis of hookworm disease.