In vivo panning for schistosome protective epitopes

描述(由申请人提供)：血吸虫病困扰着数亿人，在许多发展中国家造成大量发病率和过早死亡以及严重的经济困难。超过10亿人面临感染的风险。基因组学和蛋白质组学的发展，以及噬菌体展示和重组抗体等新技术的发展，为开发和验证与这些蠕虫寄生虫有关的假说和新的血吸虫病控制策略提供了重要的新机会。血吸虫是一种吸虫，能够在允许的脊椎动物宿主的血管系统中存活多年。尽管据报道血吸虫拥有各种免疫逃避工具，但这些血吸虫显然可以变得容易受到针对宿主暴露的被膜的抗体介导的效应器的免疫杀伤。令人信服的证据来自大鼠模型，与小鼠和人类不同，大鼠对曼氏血吸虫病具有很强的免疫力，并产生针对成虫表面表位的抗体，这些表位可以直接杀死幼虫和成虫。基于这些和其他数据，我们假设血吸虫可以通过免疫过程在体内被杀死，该免疫过程是由针对蠕虫表面表位的离散子集的保护性抗体介导的。在这项R21赠款申请中，我们建议使用一种创新的体内噬菌体展示技术来鉴定能够结合到血吸虫宿主内的表面的单链抗体(ScFv)，然后测试这些抗体是否具有直接杀死寄生虫的能力。其具体目的是：1.利用血吸虫病免疫大鼠制备的单链抗体(ScFv)噬菌体展示文库进行体内淘洗，鉴定并鉴定宿主相互作用的表面表位。#2.设计与宿主相互作用的血吸虫表位结合的重组抗体，并测试它们在小鼠体内介导寄生虫杀灭的能力。这项研究旨在确定将作为候选疫苗的保护性免疫的新靶点。此外，它将在体内产生关于宿主相互作用的寄生虫表面的生物化学的新信息，并创建可遗传修饰的单链抗体试剂，这将导致一系列独特的研究机会来研究蠕虫寄生虫的排斥和免疫逃避策略。

DESCRIPTION (provided by the applicant): Schistosomiasis afflicts several hundred million people, causing substantial morbidity and premature death as well as major economic hardship in many developing countries. Over a billion people are at risk of infection. Advances in genomics and proteomics, as well as new technologies such as phage display and recombinant antibodies, offer important new opportunities to develop and test hypotheses relating to these worm parasites and for new schistosomiasis control strategies. Schistosomes are trematode worms that are able to survive for many years within the vasculature of permissive vertebrate hosts. Although schistosomes reportedly possess a variety of immune evasive tools, these blood flukes clearly can become susceptible to immune killing by effectors mediated by antibody directed against the host-exposed tegument. Compelling evidence comes from the rat model, which, unlike mice and humans, becomes strongly immune to schistosomiasis mansoni, and produces antibodies against adult worm surface epitopes that direct the killing of larval and adult schistosomes. Based on these and other data, we hypothesize that schistosomes can be killed in vivo through an immune process that is mediated by protective antibodies directed against a discrete subset of worm surface epitopes. In this R21 grant application, we propose to employ an innovative in vivo phage display technique to identify single-chain antibodies (scFvs) able to bind to the surface of schistosomes as they reside within their host and then test these antibodies for their ability to direct killing of the parasites. The Specific Aims are: #1. Use "in vivo panning" of an antibody (scFv) phage display library prepared from rats immune to schistosomiasis to identify and then characterize host-interactive surface epitopes. #2. Engineer recombinant antibodies that bind to host-interactive schistosome epitopes and test their ability to mediate parasite killing within mice. This research is designed to identify new targets of protective immunity that will serve as vaccine candidates. Furthermore, it will produce new information on the biochemistry of the host-interactive parasite surface in vivo and create genetically modifiable scFv reagents that will lead to a range of unique research opportunities to investigate helminth parasite rejection and immune evasion strategies.