PLASMODIUM SPOROZOITE INVASION OF TARGET CELLS

这项建议的长远目标是阐明 疟原虫子孢子定位和附着于 它们在哺乳动物和蚊子宿主中的靶细胞。主要 子孢子表面蛋白，环子孢子蛋白（CS， 参与两种宿主中的靶细胞识别。先前的工作已经 显示CS与肝硫酸乙酰肝素蛋白聚糖（HSPG）结合， 这种结合在肝细胞入侵过程中发挥作用。迄今为止 涉及唾液腺识别的分子事件还没有被 描述，虽然我们有证据表明CS参与了这一过程， 过程这一进程的具体目标是：1）确定 CS亲和结合所需的HSPG结构要求 II+区结合的纯化和表征 糖胺聚糖（GAG）链。此外，利用新开发的 使我们能够跟踪循环中的子孢子的分析。2)到 确定负责结合的CS的结构特性， 利用合成肽作为竞争性抗原 抑制剂的CS结合腺体，并确定是否差异 在CS的唾液腺结合区负责 库利辛传播鸡疟原虫的研究 而不是按蚊。3)通过表达克隆， 并表征CS的唾液腺受体。 我们建议的工作与新药的开发有关 疟疾的治疗和目前对使用转基因药物的兴趣 蚊子在病媒控制项目中的作用。例如， 与CS结合的HSPG GAG链的结构特性可能导致 开发能够抑制子孢子定位的药物， 肝脏此外，对结构性质的了解 可以使用参与唾液腺侵袭的受体和配体 以产生抗感染的转基因蚊子， 疟原虫

The long-term objectives of this proposal are to elucidate the mechanisms by which Plasmodium sporozoites localize to and attach to their target cells in both mammalian and mosquito hosts. The major sporozoite surface protein, the circumsporozoite protein (CS, participates in target cell recognition in both hosts. Previous work has shown that CS binds to hepatic heparan sulfate proteoglycans (HSPGs) and that this binding functions during hepatocyte invasion. To date, the molecular events involved in salivary gland recognition have not been characterize, although we have evidence that CS participates in this process. The specific aims of this process are: 1) To define the structural requirements of HSPGs required for CS binding by affinity purification and characterization of region II-plus binding glycosaminoglycan (GAG) chains. In addition, using newly developed assays that enable us to follow sporozoites from the circulation. 2) To determine the structural properties of CS responsible for binding to mosquito salivary glands by using synthetic peptides as competitive inhibitors of CS binding to glands and to determine whether differences in the salivary gland binding region of CS is responsible for the transmission of the avian malaria parasite P. gallinaceum by Culicine rather than Anophelene mosquitos. 3) By expression cloning, to isolate and characterize the salivary gland receptor for CS. The work we propose is of relevance to the development of new drug therapies for malaria and the current interest in the use of transgenic mosquitos in vector control programs. For example, knowledge of the structural properties of HSPG GAG chains which bind to CS may lead to the development of drugs which could inhibit sporozoite localization to the liver. In addition, knowledge of the structural properties of receptors and ligands involved in salivary gland invasion could be used to generate transgenic mosquitos refractory to infection with Plasmodium.