RP3: Therapeutics Human Monoclonal Antibody Treatments for Filoviruses

埃博拉丝状病毒(EBOV)和马尔堡出血热(Marburg)是引起人类最严重的出血热，死亡率高达90%，被认为是生物恐怖主义和生物战的潜在武器。最近发表的研究表明，通过被动转移的多克隆抗体和鼠单抗可以成功地保护啮齿动物和非人灵长类动物(NHP)免受丝状病毒的感染。然而，与鼠源性、嵌合型或人源化单抗相比，全人型单抗具有重要的优势，包括它们的安全性和更强的效力。这一提议的中心假设是，EBOV和MARV感染的幸存者可能拥有循环中的B细胞，这些细胞编码自然产生的人类抗体，这些抗体可以中和病毒并预防疾病。这一假设得到了研究小组最近的一项进展的支持，该研究小组在应用中从一名MARV感染的幸存者中分离出了人mAbs。用单抗成功治疗丝状病毒感染的关键要求可能包括(A)使用高亲和力的单抗，以及(B)注射与不同病毒表位结合的单抗的“鸡尾酒”，而不是单个单抗。为检验这一可能性，将开发研究人单抗识别丝状病毒的综合试剂，这些试剂将用于实现以下特定目标：1)从自然感染后的人B细胞中分离针对EBOV和MARV的大量人单抗；2)鉴定和鉴定最具中和能力和交叉中和能力的人单抗；3)测试和优化人单抗对啮齿动物和NHP的保护；4)测试与重组VSV载体疫苗和来自RP2的抗丝状病毒小干扰RNA(SiRNA)相结合对NHP的暴露后处理。这项提议吸收了分子免疫学、分子病毒学、病毒发病机制和公共卫生方面的专家，并可使用BSL-4设施。在加蓬、刚果民主共和国和乌干达，我们可以获得对人类具有高致病性的所有五种丝状病毒(扎伊尔埃博拉病毒、苏丹埃博拉病毒、本迪布乔埃博拉病毒、象牙海岸埃博拉病毒和马鲁夫病毒)幸存者的血液，这一点很重要，因为丝状病毒的单个物种与未经历过疾病的EBOV感染阳性个体的血液之间存在显著的抗原性差异。这项拟议的研究具有重要意义，因为它将产生大量的人类单抗，这些单抗可以中和EBOV或MARV，识别最有效的单抗，并在啮齿动物和NHP中单独测试它们，并与CETR中包括的其他暴露后治疗方法结合使用。

The filoviruses Ebola (EBOV) and Marburg (MARV) cause the most severe hemorrhagic fevers in humans with the mortality rates up to 90% and are considered potential weapons for bioterrorism and biological warfare. Recently published studies demonstrated a successful protection of rodents and nonhuman primates (NHP) against filoviruses by passively transferred polyclonal antibodies (Abs) and mouse monoclonal antibodies (mAbs). However, fully human mAbs have important advantages over murine, chimeric, or humanized mAbs that include their safety and greater potency. The central hypothesis of this proposal is that survivors of EBOV and MARV Infections likely possess circulating B cells encoding naturally-occurring human Abs that neutralize virus and protect against disease. This hypothesis is supported by a recent progress of the research team included in the application in isolation of human mAbs from a survivor of MARV infection. The key requirements for successful treatment of filovirus infections with mAbs may include (A) use of high-affinity mAbs, and (B) administration of a "cocktail" of mAbs binding to the diverse viral epitopes, rather than an individual mAb. This possibility will be tested by generation of comprehensive reagents for study of filovirus recognition by human Abs which will be used for pursuing the following Specific Aims: 1) To isolate large panels of human mAbs to EBOV and MARV from the B cells of humans following natural infection; 2) To identify and characterize the most potent neutralizing and cross neutralizing human mAbs; 3) To test and optimize protection of human mAbs in rodents and NHP; 4) To test post-exposure treatment of NHPs with human mAbs in combination with recombinant VSV-vectored vaccines from RPI and anti-filovirus small interfering RNA (siRNA) from RP2. This proposal incorporates experts in molecular immunology, molecular virology, viral pathogenesis and public health, with access to BSL-4 facilities. We have access to blood of survivors of all five filovirus species highly pathogenic for humans {Zaire ebolavirus, Sudan ebolavirus, Bundibugyo ebolavirus, Ivory Coast ebolavirus, and MARV) in Gabon, Democratic Republic of Congo and Uganda, that is important due to the significant antigenic diversity between the individual species of filoviruses, and blood of individuals seropositive for EBOV infection who did not experience disease. The proposed research Is significant because it will result in generation of large panels of human mAbs that neutralize EBOV or MARV, identify the most potent mAbs and test them in rodents and NHPs on their own and in combination with the other post-exposure treatments included in the CETR.