CD4+ T CELLS RESPONDING TO SALMONELLA INFECTION

描述（改编自申请人摘要）：沙门氏菌、分枝杆菌 和组织胞浆菌是生活在 宿主巨噬细胞的吞噬体。它们都会导致艾滋病定义疾病， 研究者的长期目标是了解免疫力的发展 针对这些病原体。免疫小鼠也需要CD4 + T细胞， 抵抗沙门氏菌，提供保护宿主功能的模型 其可以成功地对抗嗜巨噬细胞感染。但 沙门氏菌免疫宿主识别的特异性细菌抗原（Ag）是 大部分未知。两种蛋白质表达在表面暴露的"隔间"， 沙门氏菌被来自免疫小鼠的CD4 + T细胞识别。一个是鞭毛 这种蛋白质也能被沙门氏菌免疫的人的T细胞识别。的 另一种是由大多数肠杆菌科表达的未鉴定的蛋白质， 包括大肠大肠杆菌、耶尔森氏菌、志贺氏菌和肠杆菌。这两种蛋白质都是 以一种暗示沙门氏菌细胞内存活的方式调节 策略是下调细菌表面抗原的表达， CD4 + T细胞。在AIM I中，CD4 + T细胞识别的沙门氏菌抗原的多样性 将使用SDS-PAGE分级分离的细菌测定来自免疫小鼠的细胞 作为Ag，这些Ag的细菌表达将在以下方面进行表征： 到使用T细胞克隆进行区室化和调节。这些研究将 提供了深入了解由CD4 + T细胞识别的Ag的性质， 环境信号影响沙门氏菌对T细胞的加工 应答在AIM 2中，编码被T细胞克隆识别的Ags的基因将被克隆。 通过表达克隆或生物化学的测序分析鉴定 纯化的Ags。这项工作可能揭示基因产物作为细胞标志物的有用 人类对沙门氏菌的免疫力在AIM 3中，鼠感染沙门氏菌 在细菌细胞的各个区室中表达模型Ag的菌株 将用于直接测试细菌Ag的区室化是否改变 它对T细胞监视的重要性。原代和次级CD4 + T细胞 将使用ELISPOT和流式细胞仪定量这些染色剂产生的反应。 流式细胞术，以及Ag特异性免疫应答对 这些菌株将在体内进行测试。这些研究将提供深入了解 CD4 + T细胞识别的抗原对病原体的反应类似于 适应了吞噬体的生活在AIM 4中，Ags的功能重要性 AIMS 1和2中鉴定的AGS将通过测试纯化的AGS的 刺激保护性免疫力对抗强毒攻击的能力 沙门氏菌。所确定的保护性AG将是优秀的候选人， 亚单位疫苗的组分和人类细胞免疫的标志物。

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.