NONHUMAN PRIMATE MODEL OF MELIODOSIS

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 类鼻疽是一种由暴露于类鼻疽伯克霍尔德氏菌引起的传染病，类鼻疽伯克霍尔德氏菌是一种主要在东南亚和北方澳大利亚发现的寄生虫。 类鼻疽被认为是一种新兴的传染病和动物流行病。B的发生率。在过去十年中，假鼻疽相关的细菌性脓毒症和支气管肺炎在流行地区显著增加。B。鼻疽假单胞菌是一种生物威胁因子，主要是因为其在低剂量（少于100个细菌细胞）下具有显著的感染性。因此，疾病控制和预防中心（CDC）已经确定了B。作为一种选定的生物制剂，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，部分依赖于暴露途径、剂量和宿主的免疫状态，尽管该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，但吸入引起的疾病最严重。目前，类鼻疽的体内研究主要限于啮齿动物疾病模型（例如，仓鼠、豚鼠）。与啮齿动物疾病模型结合的分子遗传学研究表明，编码Inv/Mxi-Spa样III型分泌系统bsa、交替和固定相σ因子R SOS应答者recA的基因介导了毒力和对宿主免疫应答的保护。 没有非啮齿类动物模型（马除外）已确定或表征，以进一步研究这种疾病。虽然密集的疫苗发现和治疗开发正在进行中，但对非人灵长类动物疾病模型的研究很少，以支持这些研究。因此，非人灵长类动物模型将代表进一步定义发病机制和研究疾病的临床相关参数的重要工具。而且，非人灵长类动物模型的建立也将使研究人员能够研究B的表型。在啮齿动物模型中表现出毒力丧失的类鼻疽假单胞菌突变体，在更合适的类人模型中。可以想象，这样的B.携带多个损伤的类鼻疽菌株将作为潜在的候选疫苗。该项目的目标是定义一种非人灵长类动物模型，该模型模拟吸入时人类类鼻疽的病理生理学，以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暴露途径、剂量和宿主的免疫状态，尽管关于该疾病的发病机制仍有许多不清楚的地方。 为了解决这一差距，我们进行了一项研究，以开发一种诱导恒河猴（Macaca mulatta）类鼻疽的气溶胶暴露方法，并表征该疾病的肺炎形式。 通过小颗粒气溶胶将6只恒河猴实验性暴露于10^3至10^6 CFU的类鼻疽伯克霍尔德氏菌1026 b。 一只动物在感染后+7天死于疾病;所有其他动物在第30天（1）或第45天（4）被人道处死。 对大体和显微镜下病变、肺和血液中的细菌负荷以及组织学变化进行评价。 气溶胶暴露于B的结果。在最高吸入剂量（H10^6 CFU）下，类鼻疽杆菌被证明是致命的（8天）;较低剂量导致局部肺部细菌感染，临床上类似于细菌性肺炎。 大体上，1只动物在PI +7天死于疾病，其特征为重度肺炎，气管粘膜、肾上腺和支气管淋巴结中存在局灶性坏死性病变。 组织学上，肺中存在严重的亚急性纤维蛋白脓性炎症、水肿、出血和坏死。 在肝脏中观察到轻度急性充血，气管粘膜、肾上腺皮质、腋窝和支气管淋巴结出现轻度至中度坏死。 其他动物在尸检时显示出极轻微的组织学变化。 通过CD 8+淋巴细胞耗竭在恢复期动物中引发细菌复发的尝试失败，表明CD 8+淋巴细胞在控制B中发挥的作用最小。类鼻疽感染。 B气溶胶暴露后恒河猴的病理学改变。假鼻疽显示出感染的剂量相关梯度，并且与人类中肺炎形式的疾病的临床病例相当。

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.