Comparative rickettsial protein profiles during tick infection

描述（由申请人提供）：立克次体是落基山斑疹热（RMSF）的病原体，是美国最严重的传染病之一。为了更好地了解立克次体传播到脊椎动物宿主的分子机制，我们将描述立克次体在蜱虫载体中的特征。我们的长期目标是利用不同致病力的立克次体之间的差异，阐明蜱中立克次体的致病机制，以开发新的方法来控制蜱传立克次体疾病。为此，我们建议使用比较蛋白质组学来评估蜱和蜱传立克次体之间的分子相互作用。这些研究的目的将表征斑点热群立克次体通过个体蜱和整个个体蜱组织传播的速率，以及确定参与传播事件的立克次体衍生分子。这些目标下的实验将确定：1）物种的差异，从内共生菌到病原体，2）不同组织中立克次体蛋白表达谱的差异，以及3）脊椎动物宿主识别的保守和独特的抗原。研究将通过二维凝胶电泳评估变异革蜱唾液腺和卵巢中立克次体的蛋白质组。此外，将通过免疫印迹分析鉴定抗原蛋白;将通过质谱法鉴定候选蛋白。比较分析将包括与人类疾病无关的立克次体蛋白质组（R。montanensis和R. bellii）。通过识别分子，确定立克次体的毒力在节肢动物，立克次体生物学的新方面将被阐明，并随后利用控制病原体。立克次体病是由立克次体的斑疹伤寒群和斑点热群成员引起的疾病。致病性立克次体通常通过节肢动物（昆虫和蜱）传播给人类。为了更好地了解立克次体毒力的机制，本项目旨在研究斑点热群立克次体和媒介蜱之间的相互作用。

DESCRIPTION (provided by applicant): Rickettsia rickettsii is the causative agent of Rocky Mountain spotted fever (RMSF), one of the most severe infectious diseases in the United States. To better understand the molecular mechanisms by which rickettsiae undergo transmission to vertebrate hosts, we will characterize rickettsiae inside the tick vector. Our long term goal is to exploit the differences between rickettsiae of varying pathogenicity and elucidate the mechanisms of rickettsial pathogenesis in ticks in order to develop novel approaches to control tick-borne rickettsial diseases. Towards this objective, we propose to use comparative proteomics to assess the molecular interactions between ticks and tick-borne rickettsiae. Aims of these studies will characterize the rate at which spotted fever group Rickettsia spread through individual ticks and throughout individual tick tissues, in addition to identifing Rickettsia-derived molecules that are involved in transmission events. Experiments under these aims will identify: 1) differences in species ranging from endosymbionts to pathogens, 2) differences in rickettsial protein expression profiles in various tissues, and 3) conserved and unique antigens recognized by the vertebrate host. Studies will assess proteomes of Rickettsia rickettsii in the salivary glands and ovaries of Dermacentor variabilis ticks by two-dimensional gel electrophoresis. Additionally, antigenic proteins will be identified by immunoblot analysis; candidate proteins will be identified by mass spectrometry. Comparative analysis will include proteomes of rickettsiae not associated with human disease (R. montanensis and R. bellii). By identifying molecules which define the virulence of rickettsiae in arthropods, novel aspects of rickettsial biology will be elucidated and subsequently exploited for control of the pathogen. Rickettsioses are diseases caused by members of the typhus group and spotted fever group of Rickettsia. Pathogenic Rickettsia are typically transmitted to humans by arthropods (insects and ticks). To better understand the mechanisms of rickettsial virulence, this project seeks to examine the interplay between spotted fever group Rickettsia and the vector tick.