CD4+ T CELLS RESPONDING TO SALMONELLA INFECTION

描述(摘自申请者摘要)：沙门氏菌、分枝杆菌 和组织胞浆体是生活在细胞内的兼性病原体 宿主巨噬细胞的吞噬小体。它们都会导致艾滋病定义的疾病，而 研究人员的长期目标是了解免疫的发展 对抗这样的病原体。免疫小鼠也需要CD4T细胞来 抵抗致命的沙门氏菌，提供保护宿主功能的模型 它可以成功地对抗嗜巨噬细胞的感染。然而， 沙门氏菌免疫宿主识别的特异性细菌抗原(AGs)是 很大程度上是未知的。两种蛋白质在暴露于表面的“隔间”中表达 沙门氏菌是由免疫小鼠的CD4T细胞识别的。一个是鞭毛 由沙门氏菌免疫的人的T细胞也能识别的蛋白质。这个 另一种是大多数肠杆菌科植物表达的一种未知蛋白质， 包括大肠杆菌、耶尔森氏菌、志贺氏菌和肠杆菌。两种蛋白质都是 以一种暗示部分沙门氏菌细胞内存活的方式进行调控 策略是下调细菌表面AGS的表达，识别 CD4T细胞。在AIM I中，CD4T识别的沙门氏菌AGS的多样性 免疫小鼠的细胞将用SDS-PAGE分离的细菌进行鉴定 作为抗原，这些抗原在细菌中的表达将受到尊重 使用T细胞克隆进行分区和调节。这些研究将 提供对CD4T细胞识别的AGS性质的洞察， 环境信号对细菌处理T细胞沙门氏菌的影响 回应。在AIM 2中，编码T细胞克隆识别的AGS的基因将是 通过表达克隆或生物化学测序分析鉴定 纯化的AGS。这项工作可能会揭示作为细胞标志的基因产品。 人类对沙门氏菌的免疫力。在AIM 3中，小鼠感染沙门氏菌 在细菌细胞不同隔室中表达模型抗原的菌株 将被用来直接测试细菌Ag的区隔是否改变 它对T细胞监测的意义。原发和继发的CD4T细胞 这些污渍产生的反应将使用ELISPOT和FLOW进行量化 细胞学和抗原特异性免疫反应的有效性 这些菌株将在体内进行测试。这些研究将提供对 CD4T细胞对病原体的类似反应识别AGS的性质 适应吞噬体内的生活。在AIM 4中，AGS的功能重要性 AIMS 1和AIMS 2中确定的将通过测试纯化的AGS 激发保护性免疫力抵御强毒攻击的能力 沙门氏菌。已确定的保护性AGS将是优秀的候选对象 人类亚单位疫苗的成分和细胞免疫标记物。

DESCRIPTION (Adapted from the Applicant's Abstract): Salmonella, Mycobacterium and Histoplasma are facultative intracellular pathogens that live inside phagosomes of host macrophages. They all cause AIDS-defining illnesses, and the investigator's long-term goal is to understand the development of immunity against such pathogens. CD4+ T cells are also required for immune mice to resist virulent Salmonella, providing a model of protective host functions which can successfully combat a macrophage-tropic infection. However, the specific bacterial antigens (Ags) recognized by Salmonella-immune hosts are largely unknown. Two proteins expressed in the surface-exposed "compartment" of Salmonella are recognized by CD4+ T cells from immune mice. One is a flagellar protein also recognized by T cells from humans immunized with Salmonella. The other is an unidentified protein expressed by most Enterobacteriaceae, including E. coli, Yersinia, Shigella, and Enterobacter. Both proteins are regulated in a fashion suggesting part of the Salmonella intracellular survival strategy is to down-regulate expression of bacterial surface Ags recognized by CD4+ T cells. In AIM I, the diversity of Salmonella Ags recognized by CD4+ T cells from immune mice will be determined using SDS-PAGE fractionated bacteria as Ag, and bacterial expression of these Ags will be characterized with respect to compartmentalization and regulation using T cell clones. The studies will provide insight into the nature of Ags recognized by CD4+ T cells, the environmental signals affecting bacterial processing Salmonella for T cell responses. In AIM 2, genes encoding Ags recognized by T cell clones will be identified by expression cloning or sequencing analysis of biochemically purified Ags. This work may reveal gene products useful as markers of cellular immunity to Salmonella in humans. In AIM 3, murine infection with Salmonella strains expressing a model Ag in various compartments of the bacterial cell will be used to directly test if compartmentalization of bacterial Ag alters its significance for surveillance by T cells. Primary and secondary CD4+ T cell responses generated by these stains will be quantified using ELISPOT and flow cytometry, and the effectiveness of an Ag-specific immune response against these strains will be tested in vivo. These studies will provide insight into the nature of Ags recognized by CD4+ T cells responding to pathogens similarly adapted for life in phagosomes. In AIM 4, the functional importance of Ags identified in AIMS 1 & 2 will be determined by testing purified Ags for their ability to stimulate protective immunity against challenge by virulent Salmonella. The protective Ags identified will be excellent candidates for components of subunit vaccines and markers of cellular immunity in humans.