Determinants of Plasmodium liver invasion

描述(申请人提供)：疟疾是最致命的传染病之一，每年估计导致200万人死亡。尽管关于寄生虫的循环有相当多的知识，但我们对寄生虫如何感染其脊椎动物宿主的理解是不完整的。当受感染的蚊子在进食血液时产生子孢子时，感染就开始了。子孢子找到了进入循环和所有器官的途径，它们专门针对和感染肝脏。先前的研究已经证实，子孢子附着在高度硫酸盐化的、肝脏特异性的糖胺多聚糖(GAG)上，这种糖胺聚糖突出肝脏血管的有窗壁，称为血窦。两种类型的细胞排列在血窦内：内皮细胞和特殊的巨噬细胞，称为库普弗细胞。已知到达肝细胞的是子孢子侵入Kupffer细胞，而不是内皮细胞，这表明发生了子孢子-Kupffer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不清楚。在初步工作中，我们已经从噬菌体展示文库中鉴定出三个能与库普弗细胞特异性结合的多肽，从而抑制子孢子的入侵。通过将这些多肽与它们在Kupffer细胞上的目标蛋白进行交联，我们将识别和表征Kupffer细胞对子孢子入侵的候选受体。我们假设这些多肽模拟与Kupffer细胞相互作用的子孢子蛋白的构象。我们将产生针对每一种多肽的抗体，并使用这些抗体来鉴定和表征可能在入侵过程中与库普弗细胞相互作用的子孢子蛋白。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。与公共卫生相关：疟疾是最致命的传染病之一，每年估计导致200万人死亡。受感染的蚊子将疟原虫子孢子传递给宿主后，它进入循环，并特异性地识别和入侵肝脏巨噬细胞(库普弗细胞)。本研究旨在鉴定与子孢子侵入肝脏Kupffer细胞相关的蛋白质(Kupffer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.