Immunotherapeutics Against Other Filovirus Threats

丝状病毒是NIAID/CDC的A类生物防御病原体，可引起严重且进展迅速的出血热，致死率为50-90%。目前还没有fda批准的针对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（EBOV）的特征最为广泛。然而，苏丹埃博拉病毒种类（SUDV）和马尔堡病毒（MARV）的爆发频率越来越高，并且可能与埃博拉病毒一样致命。此外，致病性本迪布焦埃博拉病毒（BDBV）在2012年再次出现，致死率有所提高。免疫疗法最近被证明可以在非人灵长类动物（NHPs）中提供对EBOV攻击的暴露后保护。对于MARV，免疫NHPs的恢复期血清可以提供类似的保护，这表明对所有丝状病毒的免疫治疗在人类中是可处理的。针对EBOV的单克隆抗体（mab）已经存在，并将在项目1中开发，但针对suv和MARV的单克隆抗体管道尚不完整。没有单一的suv或MARV单抗或单抗鸡尾酒疗法在NHPs中进行评估。目前，还没有中和BDBV的单抗。项目2的目标是填补丝状病毒治疗性单抗组合的这些空白。在联合研究人员中，共有216种针对SUDV或MARV的小鼠单克隆抗体可用，但尚未完全鉴定；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NHPs中的保护作用。此外，我们将从乌干达疫情，特别是2012年疫情中感染的人类幸存者身上鉴定新的SUDV和MARV单克隆抗体。该联盟的研究人员前所未有地获得了四个独立的SUDV和MARV感染幸存者队列，并在最近证明了幸存者外周血中存在中和单克隆抗体。此外，我们将鉴定和表征新的抗bdbv和广泛反应的抗丝状病毒单克隆抗体。初步ELISA研究表明，仅暴露于单一丝状病毒物种的幸存者外周血中存在SUDV、BDBV和（在某些情况下）EBOV的包膜糖蛋白（GP）交叉反应性抗体。我们将利用人杂交瘤和抗体噬菌体展示技术筛选丝状病毒感染幸存者的淋巴细胞，寻找新的BDBV和交叉中和的丝状病毒单克隆抗体。最有希望的候选药物将在啮齿动物和非人灵长类动物挑战模型中进一步评估。这项工作的终点将是为这些未充分研究和重新出现的丝状病毒建立一个强大的单克隆抗体管道。

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.