Exploiting Fc-engineering to dissect mechanisms of anti-microbial action of M. tuberculosis-specific antibodies

项目摘要 结核分枝杆菌（Mtb）是结核病（TB）的病原体，是导致死亡的主要原因， 全球范围内的单一传染源。虽然结核病是可以治愈的，但强化化疗方案加上 抗生素耐药性的出现也突出了对有效结核疫苗的需求 对于耐药性的治疗方法的发展。卡介苗（BCG），开发 在1921年，它仍然是迄今为止唯一获得许可的结核病疫苗，并且不能有效地预防结核病。 肺结核的发展。因此，治疗和疫苗设计的创新方法是 需要遏制结核病的流行。值得注意的是，尽管体液免疫具有批判性， 尽管大多数批准的疫苗对保护产生免疫应答，但对结核分枝杆菌的体液免疫仍然存在， 替补演员然而，新出现的证据支持抗体在Mtb限制中的作用。抗体可以 阻止感染的发展并防止传播。此外，小鼠不能通过激活Fc- γ受体增加了结核分枝杆菌感染后肺部的细菌负荷， 与野生型小鼠相比。这些数据强烈暗示了抗体的作用，更重要的是， 抗体恒定结构域（Fc），在保护中;然而，Fc介导的功能能够驱动保护 仍然非常不清楚。因此，本工作旨在探索抗体Fc介导的Mtb控制机制。 我们假设靶向表面暴露的Mtb抗原的抗体指导先天免疫系统， 以Fc依赖的方式限制Mtb生长，我们计划使用合理设计的 单克隆抗体的Fc工程化文库，其允许探测单个Fc增强和 修饰对抗体抗微生物活性的影响。这些抗体Fc文库将在一个实施方案中测试。 一套系统而严格的体外试验，旨在捕获潜在的不同机制 抗体作用目的1将鉴定能够驱动Mtb生长限制的抗体的功能， 目的2将探索抗体作用的细胞内机制 限制Mtb在其宿主巨噬细胞内的存活，巨噬细胞是感染期间细菌的主要生态位。总的来说， 如果成功，这项工作将有助于我们了解抗体如何导致结核病 控制，从而帮助指导下一代疫苗和/或治疗剂对抗这种全球杀手。这 工作将主要在麻省理工学院的拉根研究所和哈佛进行，哈佛是世界领先的 免疫学研究。此外，在所描述的研究项目的同时，该奖学金将提供 丰富的教学和科学交流机会，共同涵盖了全面的， 系统的毕业生培养计划。

Project Summary Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is the leading cause of death from a single infectious agent globally. While TB is curable, the intensive chemotherapeutic regimen coupled with the emergence of antibiotic resistance, has highlighted the need for an efficacious tuberculosis vaccine, as well as for the development of therapeutics robust to drug resistance. Bacillus Calmette-Guérin (BCG), developed in 1921, remains the only licensed TB vaccine to date, and does not effectively protect against the development of pulmonary TB. Consequently, innovative approaches to therapeutic and vaccine design are needed to curb the ongoing tuberculosis epidemic. Remarkably, despite the critical nature of the humoral immune response to protection by a majority of approved vaccines, humoral immunity to Mtb remains understudied. However, emerging evidence supports a role for antibodies in Mtb restriction. Antibodies can block the progression of infection and prevent spread. Moreover, mice unable to signal through activating Fc- gamma receptors have increased bacterial burden in the lung following Mtb infection, as well as decreased survival compared to wild-type mice. These data strongly implicate a role for antibodies, and more critically for the antibody constant domain (Fc), in protection; however, the Fc-mediated functions able to drive protection remain extensively unclear. Thus, this work aims explore antibody Fc-mediated mechanisms of Mtb control. We hypothesize that antibodies targeting surface exposed Mtb antigens direct the innate immune system to restrict Mtb growth in an Fc-dependent manner, and we plan to test this hypothesis using rationally designed Fc-engineered libraries of monoclonal antibodies, which allow the probing of individual Fc-enhancements and modifications for their impact on antibody anti-microbial activity. These antibody Fc-libraries will be tested in a systematic and rigorous set of in vitro assays, designed to capture potentially disparate mechanisms of antibody action. Aim 1 will identify the functions of antibodies able to drive Mtb growth restriction in whole- blood when present at the time of infection; Aim 2 will explore the intracellular mechanisms of antibody action in limiting Mtb survival within its host macrophage, the primary niche of the bacterium during infection. Overall, if successful, this work will contribute to our understanding of how antibodies may contribute to Mtb disease control, and thus help guide the next generation of vaccines and/or therapeutics against this global killer. This work will primarily be carried out at the Ragon Institute of MGH, MIT, and Harvard, a world leader in immunology research. Moreover, in parallel with the described research project, this fellowship will provide abundant teaching and science communication opportunities, to collectively encompass a comprehensive, systematic graduate training plan.