Serological assays to predict Shigella vaccine efficacy

项目摘要 大多数生活在亚洲和南亚的2-5岁儿童的中度至重度疟疾病例， 非洲撒哈拉地区被认为是志贺氏菌。感染复发导致死亡或长期 残疾。目前没有疫苗可用。虽然已经开发了多个候选人，但只有一个 很少有在人体中测试安全性和免疫原性的。然而，它们的保护功效 仍然未知。没有建立起保护的免疫相关性，这就造成了 志贺氏菌疫苗开发工作的障碍。另一个挑战是缺乏标准化的 免疫学测定，可用于协调来自不同临床研究的数据。 本申请的目标是建立和验证血清学测定，其可以预测免疫球蛋白的功效。 人类志贺氏菌候选疫苗。我们的初步数据支持抗体 具有抗微生物活性，并且血清中抗原特异性抗体的特征明显， 接种疫苗的受试者可以预测疫苗效力。 在目标1中，我们将开发和验证测定方法，以测量抗微生物药物的抗微生物功能。 志贺氏菌抗体（血清杀菌，调理吞噬杀伤和抑制巨噬细胞和 中性粒细胞毒性），使用来自试验的血清样品，其中健康成人受试者接受 Sfl 2aWC候选疫苗或安慰剂。我们将检查疫苗诱导的抗体和临床 用S. flexneri 2a，以确定一个独特的血清学谱，可以 表明疫苗有效性。 目的二：建立一种高通量多重ELISA方法，用于检测多种志贺氏菌特异性抗原。 抗体[例如侵袭质粒抗原（Ipa）IpaB、IpaC和iPad、VirG和菌株特异性LPS]， 一口井。来自Sfl 2aWC疫苗接种前和接种后以及接种前和接种后的血清 攻毒后，将使用这种新的MSD ELISA进行检测，以确定 抗原特异性抗体和对疾病的保护。 在目标3中，我们将调整确定与增强人类保护相关的测定， 将其应用于豚鼠和小鼠研究。动物模型的识别， 血清学读数预测保护性结果将是临床前疫苗的关键进展 评估，因为这些模型将更接近于人类中的疫苗性能。 这项申请涉及志贺氏菌发病机制的主要研究人员之间的伙伴关系， 位于巴尔的摩的马里兰州大学（UMB）的疫苗开发和免疫学， 里德陆军研究所（WRAIR）和约翰霍普金斯大学（JHU），这项工作已经 开发技术和试剂以促进疫苗开发工作的潜力。

PROJECT SUMMARY The majority of moderate to severe diarrheal cases in children ages 2-5 years living in Asia and Sub- Saharan Africa are attributed to Shigella. Recurrence of infection results in death or long-term disability. No vaccine is currently available. While multiple candidates have been developed, only a few have been tested in humans for safety and immunogenicity. However, their protective efficacy remains unknown. No immune correlates of protection have been established, which poses a hindrance to Shigella vaccine development efforts. An additional challenge is the lack of standardized immunological assays that could be used to harmonize data from different clinical studies. The goal of this application is to establish and validate serological assays that can predict efficacy of Shigella vaccine candidates in humans. Our preliminary data supports the hypothesis that antibodies with anti-microbial activity and a distinct profile of antigen-specific antibodies in serum from vaccinated subjects can be predictive of vaccine efficacy. In Aim 1, we will develop and validate assays to measure the anti-microbial functionality of anti- Shigella antibodies (serum bactericidal, opsonophagocytic killing and inhibition of macrophage and neutrophil toxicity) using serum samples from trials in which healthy human adult subjects received the Sfl2aWC candidate vaccine or a placebo. We will examine vaccine-induced antibody and clinical data (i.e. disease) post-challenge with S. flexneri 2a to identify a distinct serological profile that can be indicative of vaccine efficacy. In Aim 2, we will develop a high throughput multiplex ELISA to measure multiple Shigella-specific antibodies [e.g. Invasion plasmid antigens (Ipa) IpaB, IpaC and IpaD, VirG and strain specific LPS] in a single well. Serum from Sfl2aWC vaccine recipients before and after vaccination and before and after challenge will be tested with this new MSD ELISA to determine a potential association between antigen-specific antibodies and protection against disease. In Aim 3, we will adapt the assays determined to correlate with enhanced protection in humans and apply them in guinea pig and mouse studies. Identification of animal models for which the same serological readouts predict a protective outcome would be a critical advance for pre-clinical vaccine assessment as such models would more closely resemble vaccine performance in humans. This application involves a partnership between leading researchers of Shigella pathogenesis, vaccine development and immunology from the University of Maryland, Baltimore (UMB), the Walter Reed Army Institute of Research (WRAIR), and The John Hopkins University (JHU) and this work has the potential to develop technology and reagents that will facilitate vaccine development efforts.