Immunotherapeutics Against Other Filovirus Threats

丝状病毒是NIAID/CDC A类生物防御病原体，可引起严重和快速进展的出血热，对人类的致死率为50-90%。目前没有FDA批准的用于丝状病毒感染的疫苗或疗法。在丝状病毒中，扎伊尔埃博拉病毒种（EBOV）已被最广泛地表征。然而，苏丹埃博拉病毒种（SUDV）和马尔堡病毒（MARV）的爆发频率增加，并且可以与EBOV一样致命。此外，致病性本迪布焦埃博拉病毒种（BDBV）在2012年重新出现，致命性增加。最近证明免疫疗法在非人灵长类动物（NHP）中提供对EBOV攻击的暴露后保护。对于MARV，来自免疫的NHP的恢复期血清可以提供类似的保护，这表明针对所有丝状病毒的免疫疗法在人类中将是易处理的。靶向EBOV的单克隆抗体（mAb）的强大管道存在并将在项目1中开发，但SUDV和MARV mAb的管道不太完整。尚未在NHP中评价单一SUDV或MARV mAb或mAb鸡尾酒疗法。目前，没有中和BDBV mAb。项目2的目标是填补丝状病毒治疗mAb产品组合中的这些空白。在联盟研究者中，共有216种抗SUDV或MARV的鼠单克隆抗体可用，但尚未完全表征;我们将开发这些单克隆抗体，并评估它们在啮齿动物模型和NHP中的保护作用。此外，我们还将从乌干达爆发的感染幸存者中鉴定新的SUDV和MARV mAb，特别是2012年的那些。该联盟的研究人员前所未有地获得了四个独立的SUDV和MARV感染的幸存者队列，最近已经证明了中和mAb存在于幸存者的外周血中。此外，我们将鉴定和表征新的抗BDBV和广泛反应性抗丝状病毒mAb。初步的ELISA研究表明，与来自SUDV、BDBV和（在某些情况下）EBOV的包膜糖蛋白（GP）具有交叉反应性的抗体存在于仅暴露于单一丝状病毒物种的幸存者的外周血中。我们将使用人杂交瘤和抗体噬菌体展示技术来筛选丝状病毒感染的幸存者的淋巴细胞中的新的BDBV和交叉中和丝状病毒单克隆抗体。最有希望的候选物将在啮齿动物和非人灵长类动物挑战模型中进一步评价。这项工作的终点将是针对这些研究不足和重新出现的丝状病毒的mAb的强大管道。

The filoviruses are NIAID/CDC Category A biodefense pathogens that cause severe and rapidly progressing hemorrhagic fever with 50-90% human lethality. There are currently no FDA-approved vaccines or therapies for filovirus infection. Among the filoviruses, the Zaire Ebola virus species (EBOV) has been most extensively characterized. However, outbreaks ofthe Sudan Ebola virus species (SUDV) and Marburg virus (MARV) have been occurring with increased frequency and can be just as lethal as EBOV. Further, the pathogenic Bundibugyo Ebola virus species (BDBV) re-emerged in 2012 with increased lethality. Immunotherapy was recently demonstrated to provide post-exposure protection to EBOV challenge in nonhuman primates (NHPs). For MARV, convalescent sera from immunized NHPs can provide similar protection, suggesting that immunotherapy for all filoviruses will be tractable in humans. A robust pipeline of monoclonal antibodies (mAbs) targeting EBOV exists and will be developed in Project 1, but the pipeline for SUDV and MARV mAbs is less complete. Not a single SUDV or MARV mAb or mAb cocktail therapy has been evaluated in NHPs. Currently, there are no neutralizing BDBV mAbs. The goal of Project 2 is to fill these gaps in the filovirus therapeutic mAb portfolio. Among consortium investigators, a total of 216 murine mAbs against SUDV or MARV are available but have not been completely characterized; we will develop these mAbs and evaluate them for protection in rodent models and NHPs. In addition, we will identify new SUDV and MARV mAbs from human survivors of infection from outbreaks in Uganda, especially those in 2012. The consortium investigators have unprecedented access to four separate survivor cohorts of SUDV and MARV infection, and have demonstrated recently that neutralizing mAbs exist in peripheral blood of survivors. In addition, we will identify and characterize new anti-BDBV and broadly reactive anti-filovirus mAbs. Preliminary ELISA studies indicate that antibodies with cross-reactivity for the envelope glycoprotein (GP) from SUDV, BDBV and (in some cases) EBOV exist in peripheral blood of survivors who have been exposed to only a single filovirus species. We will use human hybridoma and antibody phage display technologies to screen the lymphocytes of survivors of filovirus infection for new BDBV and cross neutralizing filovirus mAbs. The most promising candidates will be further evaluated in rodent and nonhuman primate challenge models. The end-point of this work will be a robust pipeline of mAbs for these understudied and re-emerging filoviruses.