GENETIC DETERMINANTS OF PATHOGENICITY IN LEGIONELLA

描述(改编自申请者摘要)：嗜肺军团菌 是一种兼性的细胞内病原体，生长在原生动物体内 淡水资源。易感人群可能发展成暴发性肺炎 吸入受污染的水后被称为退伍军人症 气雾剂。这种机会主义的病原体极大地促进了 社区获得性和医院获得性肺炎感染评级和 与严重的发病率和死亡率有关。在人类感染期间， 在动物模型中，毒力强的嗜肺乳杆菌可引起细胞免疫 反应，包括招募和激活巨噬细胞，其服务 作为进入和随后增长的主要细胞目标，以及 产生特定的细胞因子。之前的一系列研究已经 证明了与巨噬细胞相互作用的结果取决于 嗜肺乳杆菌基因的表达，其中一些可能受到调控 通过细胞内的环境信号。只有几个基因显然 参与这种相互作用的人已经被发现，而最终的 其中任何一种在感染和疾病的发病机制中的作用 未知。一株嗜肺性乳杆菌突变株的研究 Products Protease强烈表明，动物的毒力减弱了 模型，而且这一效应可能直接与 宿主S免疫反应受损，包括细胞因子的产生。 其他研究表明，实验室传代菌株的先前生长 棘阿米巴对嗜肺乳杆菌侵袭作用的增强 巨噬细胞。这与新多肽的表达有关。 该提案的具体目的是：1)进一步界定 蛋白水解酶在嗜肺乳杆菌致病机制和宿主中的作用 免疫反应：2)检测和确定新基因的作用，目前还不是 它们参与了真核细胞的细胞内生长。 汤普金斯博士建议研究细胞生物学的相互作用 巨噬细胞野生型和突变型的鉴定和鉴定 细胞内生长的步骤由每种基因产物决定。她会的 我还使用了两种新的基因选择方法来分离和鉴定新的基因 参与了细胞内的生长。因此，该提案包含了小说 分子和遗传学方法，并利用当代显微镜 技术，包括激光共聚焦显微镜，以进一步定义和 真核细胞中军团菌的细胞生物学特性。

DESCRIPTION (Adapted from the applicant's abstract): Legionella pneumophila is a facultative intracellular pathogen that grows inside protozoans in fresh water sources. Susceptible humans may develop a fulminant pneumonia called Legionnaires disease following inhalation of contaminated water aerosols. This opportunistic pathogen contributes significantly to community-acquired and nosocomial pneumonia infection rated and is associated with serious morbidity and mortality. During human infection, and in animal models, virulent L. pneumophila elicits a cellular immune response, including recruitment and activation of macrophages, which serve as the primary cellular target for entry and subsequent growth and the production of specific cytokines. A series of prior studies has demonstrated that the outcome of the interaction with macrophages depends upon the expression of L. pneumophila genes, some of which may be regulated by intracellular environmental signals. Only a few genes that apparently are involved in this interaction have been discovered, and the definitive role of any of these in the pathogenesis of infection and disease in unknown. Studies on a L. pneumophila mutant that lacks the capacity to produce protease strongly suggest that virulence was attenuated in an animal model, and furthermore, that this effect might be directly related to impairment of the host s immune response, including cytokine production. Other studies demonstrated that prior growth of laboratory passaged strains in Acanthamoeba enhanced the invasiveness of L. pneumophila into macrophages. This was associated with the expression of new polypeptides. The specific aims of the proposal are to: 1) further define the contribution of the protease protein to L. pneumophila pathogenesis and host immune response: and 2) detect and define the role of new genes, not yet discovered, that are involved in intracellular growth in eukaryotic cells. Dr. Tompkins propose to study the cell biology of he interaction of macrophages with wild-type strains and mutants to characterize and define the steps in intracellular growth governed by each gene product. She will also use two new genetic selection methods to isolate and identify new genes involved in intracellular growth. Thus, the proposal incorporates novel molecular and genetic methods and utilizes contemporary microscopy techniques, including laser confocal microscopy, to further define and characterize the cell biology of Legionella in eukaryotic cells.