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。超过十亿人感染了这些吸血线虫寄生虫，它们附着在肠粘膜上并从撕裂的毛细血管中获取食物。尽管存在宿主炎症反应，钩虫仍可在肠道内存活数年。迄今为止，人们对成年钩虫为了生存而阻断先天性和后天性宿主免疫反应的机制知之甚少。最近从人类钩虫锡兰钩虫中克隆了与哺乳动物细胞因子巨噬细胞迁移抑制因子（MIF）同源物相对应的 eDNA。初步数据表明，重组 A. ceylanicum MIF (rAceMIF) 具有酶活性，并与人类蛋白竞争与最近鉴定的 MIF 受体 CD74 的结合。我们假设钩虫 MIF 同源物有效调节宿主免疫反应，以促进寄生虫在粘膜表面的存活。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，包括互变异构酶活性、巨噬细胞迁移和促炎细胞信号传导。将表征 rAceMIF 与 CD74 结合的动力学，并使用 X 射线晶体学阐明其三维结构。将在体内对 AceMIF 基因表达进行表征，以记录其阶段特异性，并通过免疫组织化学对成虫钩虫内 AceMIF 产生的来源进行表征。平行研究将使用完全允许的锡兰弧菌动物模型来分析宿主 MIF 响应钩虫感染的组织特异性表达。 AceMIF 在钩虫贫血和生长迟缓发病机制中的作用也将使用疫苗和靶向基因沉默方法来表征。将通过 ELISA 监测对免疫接种的反应，并将使用临床参数和蠕虫负荷测量来评估针对 AceMIF 的抗体预防钩虫贫血和生长延迟的程度。这些研究将表征这种多功能人类细胞因子的新型蠕虫同源物，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.