NONHUMAN PRIMATE MODEL OF MELIODOSIS

非人类灵长类动物鼻根瘤模型

• 批准号: 8358092
• 负责人: CHAD J. ROY
• 金额: $ 3.72万
• 依托单位: TULANE UNIVERSITY OF LOUISIANA
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-05-01 至 2012-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8358092
• 关键词: Acute; Address; Adrenal Cortex; Adrenal Glands; Aerosols; Animals; Area; Australia; Autopsy; Axilla; Bacteria; Bacterial Infections; Bacterial Pneumonia; Biological; Biological Products; Blood; Breathing; Bronchial Lymph Node; Bronchopneumonia; Burkholderia pseudomallei; CD8-Positive T-Lymphocytes; Cavia; Cells; Centers for Disease Control and Prevention (U.S.); Clinical; Communicable Diseases; Coupled; Disease; Disease model; Dose; Edema; Emerging Communicable Diseases; Equus caballus; Exhibits; Exposure to; Functional disorder; Funding; Genes; Goals; Grant; Hamsters; Hemorrhage; Histologic; Human; Immune; Immune response; Incidence; Infection; Inflammation; Lesion; Liver; Lung; Lymphocyte Depletion; Macaca mulatta; Mediating; Melioidosis; Methods; Microscopic; Modeling; Molecular; Molecular Genetics; Mucous Membrane; National Center for Research Resources; Necrosis; Pathogenesis; Pathologic; Phase; Phenotype; Play; Pneumonia; Primate Diseases; Primates; Principal Investigator; Recrudescences; Reporting; Research; Research Infrastructure; Research Personnel; Resources; Rodent Diseases; Rodent Model; Role; Route; Sepsis; Sigma Factor; Son of Sevenless Proteins; Source; Southeastern Asia; Symptoms; Syndrome; Time; Type III Secretion System Pathway; United States National Institutes of Health; Vaccines; Virulence; clinically relevant; cost; disorder prevention; in vivo; mutant; nonhuman primate; particle; subcutaneous; therapeutic development; tool; vaccine candidate

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Melioidosis is an infectious disease caused by exposure to Burkholderia pseudomallei, a saprophyte found primarily in Southeast Asia and Northern Australia. Melioidosis is considered an emerging infectious disease and epizoonotic agent. Incidence of B. pseudomallei-associated bacterial sepsis and bronchopneumonia has significantly increased in endemic areas over the past decade. B. pseudomallei is a biological threat agent primarily because of its remarkable infectivity at a low (less than 100 bacterial cells) dose. As a result, the Centers of Disease Control and Prevention (CDC) have identified B. pseudomallei as a select biological agent, with a high potential for misuse against masses. Melioidosis is associated with a severe clinical syndrome which is dependant in part on the route of exposure, dose, and immune status of the host, although much remains unclear about pathogenesis of the disease. Although infection from subcutaneous inoculation is not uncommon, inhalation produces the most severe disease. Presently, in vivo study of melioidosis has been mostly restricted to rodent disease models (e.g., hamster, guinea pig). Molecular genetic studies coupled with rodent disease models have implicated genes encoding Inv/Mxi-Spa-like Type III secretion system bsa, alternate and stationary phase sigma factor R SOS responder recA in mediating virulence and protection from host immune response. No nonrodent model (other than equine) have been identified or characterized to further study this disease. Although intensive vaccine discovery and therapeutic development is ongoing, there has been minimal research into a nonhuman primate disease model to support these studies. As such, a nonhuman primate model would represent a significant tool to further define pathogenesis and study the clinically relevant parameters of the disease. Moreover, the establishment of a nonhuman primate model will also allow researchers to study the phenotype of B. pseudomallei mutants that exhibit loss of virulence in rodent models, in a more appropriate human-like model. It is conceivable that such B. pseudomallei strains carrying multiple lesions will serve as potential vaccine candidates. The goals of this project are to define a nonhuman primate model that emulates the reported pathophysiology of human melioidosis when inhaled, to identify molecular correlates in the bacterium during host-infection and conditions that mimic it; and define immunological parameters associated with the disease. The severe clinical symptom of melioidosis is dependant in part on the route of exposure, dose, and immune status of the host, although much remains unclear about pathogenesis of the disease. To address this gap, we performed a study to develop an aerosol exposure method for induction of melioidosis in rhesus macaques (Macaca mulatta) and characterize the pneumonic form of the disease. Six rhesus macaques were experimentally exposed by small particle aerosol to 10^3 to 10^6 CFU of Burkholderia pseudomallei 1026b. One animal succumbed to disease +7d postinfection; all other animals were euthanized at day 30 (1) or 45 (4). Gross and microscopic lesions, bacterial burden in lungs and blood, and histologic changes were evaluated. Results of aerosol exposure to B. pseudomallei proved lethal (8 days) at the highest inhaled doses (H10^6 CFU); lower doses resulted in a localized pulmonary bacterial infection clinically similar to bacterial pneumonia. Grossly, the one animal succumbing to disease +7d PI was characterized as a severe pneumonia with focal necrotizing lesions in the tracheal mucosa, adrenal and bronchial lymph nodes. Histologically, there was severe subacute fibrinopurulent inflammation, edema, hemorrhage, and necrosis in the lung. Milder acute congestion was observed in the liver, with mild to moderate necrosis in the tracheal mucosa, adrenal cortex, axillary, and bronchial lymph nodes. The other animals showed minimal histologic changes at the time of necropsy. An attempt to initiate bacterial recrudescence in convalescent animals via CD8+ lymphocyte depletion failed, suggesting that CD8+ lymphocytes play a minimal role in controlling B. pseudomallei infection. Pathologic findings in rhesus macaques after aerosol exposure to B. pseudomallei show a dose-related gradient for infection and are comparable to clinical cases of the pneumonic form of the disease in humans.

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 类鼻疽病是一种传染病，由接触假性伯克霍尔德氏菌引起，这种腐生植物主要发现于东南亚和澳大利亚北部。类鼻疽被认为是一种新出现的传染病和人畜共患病原体。在过去的十年中，在流行地区，假鼻疽相关性细菌性败血症和支气管肺炎的发病率显著增加。假鼻疽杆菌是一种生物威胁因子，主要是因为它在低剂量(不到100个细菌细胞)下具有显着的传染性。因此，疾病控制和预防中心(CDC)已将假鼻疽杆菌确定为一种精选的生物制剂，具有对群众滥用的高可能性。类鼻疽病是一种严重的临床综合征，部分取决于暴露途径、剂量和宿主的免疫状态，尽管疾病的发病机制仍不清楚。虽然皮下接种引起的感染并不少见，但吸入会导致最严重的疾病。目前，类鼻疽病的活体研究大多局限于啮齿动物疾病模型(如仓鼠、豚鼠)。结合啮齿动物疾病模型的分子遗传学研究表明，编码Inv/MXI-SpA样III型分泌系统BSA、交替和静止时相Sigma因子R SOS响应器recA的基因在介导毒力和保护宿主免疫反应中发挥作用。除了马以外，还没有确定或表征非啮齿动物模型来进一步研究这种疾病。尽管密集的疫苗发现和治疗开发正在进行中，但对非人类灵长类疾病模型的研究一直很少，以支持这些研究。因此，非人灵长类动物模型将是进一步定义发病机制和研究疾病临床相关参数的重要工具。此外，非人类灵长类动物模型的建立也将使研究人员能够在更合适的类似人类的模型中，研究在啮齿动物模型中表现出毒力丧失的假鼻疽突变体的表型。可以想象，这些携带多个皮损的假鼻疽杆菌菌株将成为潜在的候选疫苗。该项目的目标是定义一个非人类灵长类动物模型，模拟已报道的人类类鼻疽吸入时的病理生理学，确定宿主感染期间细菌中的分子相关性和模拟它的条件；并定义与疾病相关的免疫学参数。类鼻疽的严重临床症状部分取决于接触途径、剂量和宿主的免疫状态，尽管疾病的发病机制仍不清楚。为了解决这一差距，我们开展了一项研究，旨在开发一种气雾剂暴露方法来诱导恒河猴(猕猴)类鼻疽病，并表征这种疾病的肺炎形式。用小颗粒气雾剂对6只恒河猴暴露于假鼻孔伯克霍尔德氏菌1026b的10^3~10^6 CFU。一只动物在感染后7d死于疾病；所有其他动物在第30(1)天或45(4)天被安乐死。评估大体和显微损害、肺和血液中的细菌负荷以及组织学变化。在最高吸入剂量(H10^6CFU)下，气雾剂暴露于假鼻疽杆菌的结果被证明是致命的(8天)；较低剂量导致临床上类似细菌性肺炎的局限性肺部细菌感染。大体而言，1只动物死于疾病+7d，其特征是严重肺炎，并伴有气管粘膜、肾上腺和支气管淋巴结局灶性坏死性病变。组织学上，肺内有严重的亚急性化脓性炎症、水肿、出血和坏死。肝脏急性充血程度较轻，气管粘膜、肾上腺皮质、腋窝和支气管淋巴结轻度至中度坏死。其他动物在尸检时显示出最小的组织学变化。一项试图通过CD8+淋巴细胞耗尽在恢复期动物中启动细菌复发的尝试失败了，这表明CD8+淋巴细胞在控制假鼻疽杆菌感染方面起到的作用很小。气雾剂暴露于假鼻炎杆菌后，猕猴的病理结果显示出感染的剂量相关梯度，与人类肺炎形式的临床病例相似。