HOST-PARASITE INTERACTIONS THAT DETERMINE THE RATE OF B BURGDORFERI IN VIVO

了解细胞免疫反应清除的能力 伯氏疏螺旋体是莱姆病的病原体，对 正确认识莱姆病的发病机制。我们已经展示了 以前，巨噬细胞在体内迅速摄取并杀死伯氏杆菌 体外培养。尽管有这种杀戮，我们还是偶尔观察到与细胞相关的 持续的螺旋体和这样的螺旋体被重新培养。在体外， 我们已经从未发炎的腹膜腔分离出螺旋体。 慢性感染的小鼠，尽管存在常驻巨噬细胞。我们 将在三年内研究体内正常杀伤机制的失败 方法：体外、体外、原位。我们的方法包括 生化分析与定量共聚焦荧光和电子 显微镜。 具体地说，在目标1中，我们将确定动力学、程度和机制 在体外吞噬细胞杀灭伯氏杆菌是必要的第一步 目标二：测试腹膜巨噬细胞的杀伤能力 从感染伯氏杆菌的小鼠分离，在存在和不存在的情况下 可能含有免疫调节成分的灌洗液。万一 持续性螺旋体的特性是导致它们 过关不合格时，我们也会检查未培养的分离螺旋体 来自受感染动物的免疫荧光和电子显微镜 表达的表面蛋白的标记。最后，在目标3中，我们将研究 这些问题利用莱姆疏螺旋体病的心脏受累情况进行了原位调查， 对于这些目的来说，理想的疾病表现形式，如 问题似乎主要是由巨噬细胞介导的。我们将研究 感染小鼠心脏和其他组织的切片并评估 巨噬细胞是否吞噬和降解螺旋体 心脏；确定巨噬细胞是激活还是失活 通过一组标记抗体；最后，是否修改状态 巨噬细胞与细胞因子的激活可以影响 莱姆型心脏炎的进展--具有明显治疗前景 这意味着什么。整体而言，我们期望这些研究能提供一个 吞噬细胞功能完整性的全貌 伯氏杆菌感染伯氏杆菌的宿主。

Understanding the capacity of the cellular immune response to clear Borrelia burgdorferi, the etiologic agent of Lyme disease, is essential to a proper understanding of the pathogenesis of Lyme disease. We have shown previously that macrophages take up and kill B. burgdorferi rapidly in vitro. Despite this killing, we have observed occasional cell-associated persistent spirochetes and such spirochetes have been recultured. Ex vivo, we have isolated spirochetes from the uninflammed peritoneal cavity of chronically-infected mice despite the presence of resident macrophages. We will examine this failure of normal killing mechanisms in vivo in three ways: in vitro, ex vivo, and in situ. Our methodologies include biochemical assays and quantitative confocal fluorescent and electron microscopy. Specifically, in Aim 1 we will identify kinetics, extent, and mechanisms of killing of B. burgdorferi by phagocytes in vitro as a necessary first step to Aim 2: testing the killing capacity of peritoneal macrophages isolated from B. burgdorferi-infected mice, in the presence and absence of lavage fluid which may contain immunomodulatory elements. In case characteristics of the persistent spirochetes are responsible for their faulty clearance, we will also examine uncultured spirochetes isolated from infected animals, by immunofluorescent and electron microscopic labeling of expressed surface proteins. Finally, in Aim 3, we will study these questions in situ using the cardiac involvement of Lyme borreliosis, an ideal disease presentation for these purposes, as the lesion in question appears to be primarily macrophage-mediated. We will examine sections of cardiac and other tissue from infected mice and evaluate whether the macrophages are phagocytosing and degrading spirochetes in the heart; whether the macrophages are activated or deactivated as determined by a panel of marker antibodies; and finally, whether modifying the state of activation of the macrophages with cytokines can influence the progression of Lyme carditis, a prospect with obvious therapeutic implications. Taken as a whole, we expect these studies to provide a comprehensive picture of the functional integrity of phagocytic cells in a host infected with B. burgdorferi.