Molecular and Immunologic Analysis of the Pathobiology of Human Anthrax

描述（由申请人提供）：本申请是2003年首次授予的CCHI资助的第二次竞争性更新，用于研究人类对炭疽芽孢杆菌和毒素疫苗的免疫反应，该疫苗目前已部署给数千名美国军队。最初申请的目的是：（a）研究人类对挑战性疫苗的免疫反应，（B）了解吸入形式疾病的高致死性机制，（c）了解宿主对病原体反应的细胞基础。我们发表的研究结果表明，与流行的观点相反，吸入性炭疽的高死亡率是由于细菌败血症，而不是炭疽毒素。在最近的资助周期中，我们取得了开创性的发现，即肽聚糖（PGN）和所有人类中存在的预先存在的抗PGN抗体之间的免疫复合物可能是伴随B感染的大规模炎症的来源。炭疽病最后，我们发现，尽管在繁重的疫苗接种计划中已经接种了6次以上，但几乎可以肯定有30%的疫苗接种者没有受到保护。 在这次更新申请中，我们将跟进这些令人兴奋的发现，以确定： (a)炭疽孢子如何从肺泡转移到纵隔淋巴结。 (b)PGN如何触发人体免疫细胞的抗菌反应以及炭疽毒素如何影响反应。 (c)PGN-抗PGN免疫复合物如何影响疾病的结果。 (d)为什么疫苗在刺激生发中心B细胞成熟方面不完美，以及毒素损伤的红细胞增多症引起的组蛋白升高是否有助于炎症。 我们的工作得到了3个科学核心的支持：一个动物核心，应用了在上一个资助周期中建立的非人灵长类动物模型;一个流式细胞术核心，具有最先进的能力;和一个人抗体核心，将使用我们研究所发明的技术制造重组人单克隆抗体。 本更新申请中的研究重点和主题围绕PGN、炭疽毒素和炭疽毒素疫苗在人类免疫应答中的关键作用进行组织。他们有很大的潜力，以确定新的手段中断这种模式革兰氏阳性病原体引起的病理。 相关性：B。炭疽病是生物恐怖主义的高度相关和重要媒介。虽然向军事人员提供了疫苗，但不向普通公民提供，而且其效力非常值得怀疑。我们在理解B方面取得了很大的进展。炭疽菌感染的人类，并提出新的研究，以扩大我们发表的研究结果。 项目1：菌血症期间毒素介导的人PBMC应答抑制 项目负责人（PL）：Ballard，Jimmy 描述（由申请人提供）：菌血症可导致感染个体的败血性休克和死亡，但人类对菌血症的许多方面仍知之甚少。特别是宿主对细菌组分的反应和人类单核细胞中毒力因子对这些反应的抑制尚未得到充分研究，这限制了新疗法的开发。使用炭疽芽孢杆菌作为模型系统，我们正在研究炎症刺激（肽聚糖）和炭疽毒素对这种刺激的反应的调制。特别是，我们正在表征PGN对抗菌剂的诱导作用，并研究炭疽致死毒素（而不是水肿毒素）如何抑制这种反应。该项目的第一个目的是表征BaPGN诱导的抗微生物反应及其在人PBMC中由炭疽毒素的调节。第二个目的是表征LT和ET调节炎症和抗菌反应的不同机制。最后的目的是研究BaPGN诱导的促炎/抗微生物因子及其在体内模型中被炭疽毒素抑制之间的相互作用。完成这些目标将解决我们的总体目标，即定义引起菌血症的革兰氏阳性病原体和宿主对该病原体的反应之间发生的分子和细胞事件。 相关性：菌血症和感染性休克是严重的医学疾病，治疗选择有限。我们的研究结果将提供有关这种疾病事件的信息，特别关注人类的这一过程以及治疗感染者的可能方法。

DESCRIPTION (provided by applicant): The present application is the second competing renewal of a CCHI grant first awarded in 2003 to study human immune response to Bacillus anthracis and the toxin vaccine that is currently administered to the thousands of deployed US military. The goals of the original application were: (a) To study the human immune response to a challenging vaccine, (b) To understand the mechanism for the high lethality of the inhalation form of the disease, (c) To understand the cellular basis of the host response to the pathogen. Our published findings show, in contrast to prevailing views, that the high rate of mortality in inhalation anthrax is due to bacterial sepsis and not the anthrax toxins. In the most recent funding cycle, we made the seminal discovery that immune complexes between peptidoglycan (PGN) and pre-existing anti-PGN antibodies present in all humans may be the source of the massive inflammation accompanying infection by B. anthracis. Lastly, we discovered that fully 30% of vaccinees are almost certainly unprotected despite having been immunized more than 6 times in an onerous vaccine schedule. In this renewal application, we will follow up on these exciting discoveries to determine: (a) How do anthrax spores move from the alveoli to the mediastinal lymph nodes. (b) How PGN triggers an antimicrobial response by human immune cells and how anthrax toxins affect the response. (c) How PGN-anti-PGN immune complexes influence the outcome of the disease. (d) Why the vaccine is imperfect in stimulating the maturation of germinal center B cells, and whether elevated histones caused by toxin-impaired efferocytosis contributes to inflammation. Our work is supported by 3 scientific cores: An animal core that applies a non-human primate model established in the previous funding cycle; a flow cytometry core that has state-of-the-art capacity; and a human antibody core that will make recombinant human monoclonal antibodies using technology that was invented at our institute. The studies in this renewal application-are focused and thematically organized around the key roles of PGN, the anthrax toxins and the anthrax toxin vaccine in the human immune responses. They have great potential to identify novel means of interrupting the pathology caused by this model Gram-positive pathogen. RELEVANCE: B. anthracis is highly relevant and important agent of bioterrorism. Although a vaccine is provided to military personnel, it is not given to private citizens and is of highly questionable efficacy. We have made great progress in understanding B. anthracis infections in humans and propose novel studies to expand our published findings. Project 1: Toxin-Mediated Suppression of Human PBMC Responses During Bacteremia Project Leader (PL): Ballard, Jimmy DESCRIPTION (provided by applicant): Bacteremia can lead to septic shock and death in infected individuals, yet many aspects of bacteremia remain poorly understood in humans. In particular the host responses to bacterial components and the suppression of these responses by virulence factors in humans mononuclear cells has not been fully investigated and this has limited the development of new therapeutics. Using Bacillus anthracis as a model system we are investigating inflammatory stimuli (peptidoglycan) and modulation of responses to this stimuli by anthrax toxin. In particular we are characterizing the induction of antimicrobials by PGN and studying how anthrax lethal toxin, but not edema toxin, suppresses this response. The first aim of this project is to characterize the BaPGN-induced antimicrobial response and its modulation by anthrax toxin in human PBMCs. The second aim is to characterize the differential mechanisms by which LT and ET modulate inflammatory and antimicrobial responses. The final aim is to examine the interplay between BaPGN-induced proinflammatory/antimicrobial factors and their suppression by anthrax toxin in an in vivo model. Completing these aims will address our overall goal of defining the molecular and cellular events occurring between a gram positive pathogen that causes bacteremia and the host responses to that pathogen. RELEVANCE: Bacteremia and septic shock are serious medical conditions and treatment options are limited. Results from our studies will provide information about this disease event, with a specific focus on this process in humans and possible ways to treat infected individuals.