In vivo panning for schistosome protective epitopes

描述（由申请人提供）：血吸虫病影响数亿人，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10亿人面临感染风险。基因组学和蛋白质组学的进展，以及噬菌体展示和重组抗体等新技术，提供了重要的新机会，开发和测试有关这些蠕虫寄生虫的假设和新的血吸虫病控制策略。血吸虫是一种蠕虫能够在允许的脊椎动物宿主的脉管系统中存活多年。尽管据报道，血吸虫体具有多种免疫逃避工具，但这些血吸虫显然可以变得对由针对宿主暴露的被膜的抗体介导的效应物的免疫杀伤敏感。令人信服的证据来自大鼠模型，与小鼠和人类不同，它对曼氏血吸虫病具有强烈的免疫力，并产生针对成虫表面抗原决定簇的抗体，这些抗原决定簇直接杀死幼虫和成虫的寄生虫。基于这些和其他数据，我们假设，通过针对蠕虫表面表位的离散子集的保护性抗体介导的免疫过程，可以在体内杀死寄生虫体。在这项R21授权申请中，我们建议采用一种创新的体内噬菌体展示技术来鉴定能够与寄生虫体表面结合的单链抗体（scFv），因为它们驻留在宿主体内，然后测试这些抗体直接杀死寄生虫的能力。 具体目标是：#1。使用从对血吸虫病免疫的大鼠制备的抗体（scFv）噬菌体展示文库的“体内淘选”来鉴定并表征宿主相互作用的表面表位。#2.工程重组抗体结合宿主相互作用的噬菌体表位，并测试其介导小鼠体内寄生虫杀死的能力。这项研究旨在确定保护性免疫的新靶点，这些靶点将作为候选疫苗。此外，它将产生新的信息的生物化学宿主相互作用的寄生虫表面在体内，并创建遗传修饰的scFv试剂，这将导致一系列独特的研究机会，调查蠕虫寄生虫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.