Determinants of Plasmodium liver invasion

描述（由申请人提供）：疟疾是最致命的传染病之一，估计每年造成200万人死亡。尽管关于寄生虫周期有相当多的知识存在，但我们对寄生虫如何感染脊椎动物宿主的理解是不完整的。当被感染的蚊子在吸血时传播孢子虫时，感染就开始了。孢子子找到了进入血液循环的途径，并通过所有器官，它们专门针对并感染肝脏。先前的研究已经证实，孢子子附着在高度硫酸化的肝脏特异性糖胺聚糖（GAGs）上，这些糖胺聚糖突出了肝脏血管的开窗壁，称为窦状体。两种细胞类型：内皮细胞和特化巨噬细胞，称为库普弗细胞。众所周知，为了到达肝细胞，孢子子侵入库普弗细胞，而不是内皮细胞，这表明发生了孢子子-库普弗识别。尽管它对感染的结果很重要，但这一识别步骤的分子基础在很大程度上仍然未知。在初步工作中，我们已经从噬菌体展示文库中鉴定出三种肽，它们特异性地与库普弗细胞结合，从而抑制孢子子的入侵。通过将多肽与其靶蛋白交联在Kupffer细胞上，我们将鉴定和表征候选的Kupffer细胞受体，用于孢子子入侵。我们假设这些肽模拟了与库普弗细胞相互作用的孢子子蛋白的构象。我们将产生针对每种肽的抗体，并使用这些抗体来识别和表征可能在入侵期间与库普弗细胞相互作用的孢子子蛋白。这些蛋白质有可能成为开发预防肝脏感染的疟疾疫苗的候选者。公共卫生相关性：疟疾是最致命的传染病之一，估计每年造成200万人死亡。被感染的蚊子将疟原虫孢子体传递给宿主后，进入血液循环，特异性识别并侵入肝巨噬细胞（库普弗细胞）。本项目旨在鉴定和表征参与肝库普弗细胞的子孢子侵染的蛋白（库普弗受体和子孢子配体）。

DESCRIPTION (provided by applicant): Malaria is one of the deadliest infectious diseases and kills an estimated 2 million persons every year. Even though a considerable body of knowledge exists on the parasite cycle, our understanding of how the parasite infects its vertebrate host is incomplete. Infection is initiated when an infected mosquito delivers sporozoites at the time of blood feeding. The sporozoites find their way to the circulation and of all organs through which they transit, they specifically target and infect the liver. Previous work has established that sporozoites attach to highly sulfated, liver-specific glycosaminoglycans (GAGs) that protrude the fenestrated walls of the liver blood vessels, called sinusoids. Two cell types line the sinusoids: endothelial cells and specialized macrophages, termed Kupffer cells. It is known that to reach the hepatocytes, sporozoites invade Kupffer cells, not endothelial cells, indicating that sporozoite-Kupffer recognition takes place. Despite its importance for the outcome of infection, the molecular basis for this recognition step remains largely unknown. In preliminary work we have identified three peptides from a phage display library that bind specifically to Kupffer cells causing an inhibition of sporozoite invasion. By crosslinking the peptides to their target protein on the Kupffer cells, we will identify and characterize candidate Kupffer cell receptors for sporozoite invasion. We hypothesize that the peptides mimic the conformation of sporozoite proteins that interact with the Kupffer cells. We will produce antibodies against each of the peptides and use these antibodies to identify and characterize the sporozoite proteins that presumably interact with the Kupffer cells during invasion. Such proteins have the potential of becoming candidates for development of a malaria vaccine that prevents liver infection. PUBLIC HEALTH RELEVANCE: Malaria is one of the deadliest infectious diseases and kills an estimated 2 million persons every year. After an infected mosquito delivers Plasmodium sporozoites to its host it enters the circulation and specifically recognize and invade liver macrophages (Kupffer cells). This project is to identify and characterize the proteins (Kupffer receptors and sporozoite ligands) involved in sporozoite invasion of liver Kupffer cells.