Evolutionary lead optimization for immunotherapy of Marburg & Ebola viruses

描述（由申请人提供）：本提案旨在开发一种新的免疫疗法，用于预防和治疗线状病毒家族的马尔堡病毒和埃博拉病毒的危及生命的感染，这些感染可能被操纵为构成严重公共威胁的生物武器。该建议建立在甘露糖结合凝集素（MBL）是先天免疫的广谱分子这一事实的基础上。这种血清蛋白可识别多种病原体，如细菌、寄生虫和包括丝状病毒在内的病毒。初步数据表明，重组人MBL （rHuMBL）可识别埃博拉病毒和马尔堡病毒的包膜糖蛋白。这一观察结果，加上MBL在一线宿主防御中的作用，使其成为丝状病毒暴露前后使用的免疫治疗剂的有力候选者。该项目的一个关键目标是评估临床级rHuMBL，该rHuMBL已在第1期临床研究中使用，以及MBL的第二代衍生物，该衍生物含有L-ficolin（另一种凝集素样蛋白）的一部分。初步研究表明，这些新的凝集素嵌合体结合甘露聚糖，与装饰丝状病毒的碳水化合物相同。这项拨款提案将利用马萨诸塞州总医院发育免疫学实验室的基础设施、先天免疫领域研究人员的丰富科学经验、开发治疗性rHuMBL的丹麦生物技术公司natimmune的产品开发专业知识、以及美国陆军传染病医学研究所高度专业化的资源，在那里建立了小鼠和豚鼠丝状病毒感染模型。我们将在体外使用丝状病毒糖蛋白假型HIV颗粒，评估rHuMBL和凝集素嵌合体激活凝集素补体途径和调节吞噬功能的功效。此外，我们将研究这些凝集素在MBL、补体成分3、ficolin-A（小鼠形式的L-ficolin）或其组合缺陷的转基因小鼠株中的保护作用，以阐明每种先天免疫分子在受到天然丝状病毒致命攻击的啮齿动物中的相对作用。本提案的最终目标是开发一种rHuMBL制剂或其衍生物，可用于接触丝状病毒的士兵或平民的预防和/或治疗。

DESCRIPTION (provided by applicant): This proposal is aimed at developing a novel immunotherapeutic that will prevent and treat life-threatening infections with Marburg and Ebola viruses of the filovirus family that might be manipulated as bioweapons posing grave public threats. The proposal builds on the fact that the mannose-binding lectin (MBL) is a broad-spectrum molecule of innate immunity. This serum protein recognizes a wide range of pathogens, such as bacteria, parasites and viruses including filoviruses. Preliminary data indicate that recombinant human MBL (rHuMBL) recognizes the envelope glycoproteins of Ebola and Marburg viruses. This observation, together with the role of MBL in first line host defense, makes it a strong candidate as an immunotherapeutic agent for use before and/or after exposure to filoviruses. A key goal of this project is to evaluate clinical grade rHuMBL that has been used in Phase 1 clinical studies in the first instance, and second generation derivatives of MBL that incorporate a part of L-ficolin, another lectin-like protein. Preliminary studies demonstrated that these novel lectin chimeras bind mannan, the same carbohydrate that adorns filoviruses. This grant proposal will leverage the infrastructure of the Laboratory of Developmental Immunology at Massachusetts General Hospital, the extensive scientific experience of the investigators in the field of innate immunity, the product development expertise of Natlmmune, a Danish biotechnology company that developed therapeutic rHuMBL, and the highly specialized resources of the United States Army Medical Research Institute for Infectious Diseases where mouse and guinea pig models of filovirus infection have been established. We will evaluate the efficacy of rHuMBL and lectin chimeras to activate the lectin complement pathway and to modulate phagocytic function in vitro using HIV particles pseudotyped with filovirus glycoproteins. Furthermore, we will investigate the protective efficacy of these lectins in strains of genetically modified mice deficient in MBL, complement component 3, ficolin-A (murine form of L-ficolin) or combinations thereof to elucidate the relative roles of each innate immune molecule in rodents fatally challenged with native filoviruses. The ultimate goal of this proposal is to develop a formulation of rHuMBL or a derivative thereof that could be used prophylactically and/or therapeutically by soldiers or civilians exposed to filoviruses.