CD4+ T CELLS RESPONDING TO SALMONELLA INFECTION

CD4 T 细胞对沙门氏菌感染的反应

基本信息

批准号：
6836493
负责人：
BRAD T COOKSON
金额：
$ 33.81万
依托单位：
UNIVERSITY OF WASHINGTON
依托单位国家：
美国
项目类别：
财政年份：
2001
资助国家：
美国
起止时间：
2001-01-01 至 2007-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6836493
关键词：
SDS polyacrylamide gel electrophoresis Salmonella infections bacteria infection mechanism bacterial antigens bacterial genetics bactericidal immunity biomarker cellular immunity enzyme linked immunosorbent assay flow cytometry genetic mapping genetic strain helper T lymphocyte laboratory mouse phagocytosis vesicle /vacuole virulence

项目摘要

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.

描述（改编自申请人的摘要）：沙门氏菌，分枝杆菌组织肿瘤是生活在内部的兼性细胞内病原体宿主巨噬细胞的吞噬体。它们都导致定义疾病的艾滋病，以及研究者的长期目标是了解免疫的发展针对这种病原体。免疫小鼠也需要CD4+ T细胞抵抗有毒的沙门氏菌，提供保护性宿主功能的模型可以成功地抵抗巨噬细胞 - 授予感染。但是，沙门氏菌免疫宿主识别的特定细菌抗原（AGS）是在很大程度上未知。在表面暴露的“隔室”中表达的两种蛋白质沙门氏菌被免疫小鼠的CD4+ T细胞识别。一个是鞭毛蛋白质也被人类的T细胞识别，用沙门氏菌免疫。这其他是大多数肠杆菌科表示的不明蛋白质，包括大肠杆菌，Yersinia，Shigella和Enterobacter。两种蛋白质都是以一种建议的一部分细胞内生存的方式调节策略是下调由细菌表面AG的表达 CD4+ T细胞。在AIM I中，CD4+ T认可的沙门氏菌AG的多样性免疫小鼠的细胞将使用SDS-PAGE分级细菌确定作为Ag和这些AG的细菌表达将以尊重为特征使用T细胞克隆分隔和调节。研究会提供有关CD4+ T细胞识别的AG的性质的见解，影响T细胞细菌加工沙门氏菌的环境信号回答。在AIM 2中，编码由T细胞克隆识别的AG的基因将是通过表达克隆或生化分析来鉴定纯化的AGS。这项工作可能揭示了有用的基因产物作为细胞的标记对人类沙门氏菌的免疫力。在AIM 3中，用沙门氏菌感染鼠类在细菌细胞的各个隔室中表达AG模型的菌株将用于直接测试细菌Ag的分室化是否改变它对T细胞监视的重要性。初级和次级CD4+ T细胞这些污渍产生的响应将使用ELISPOT和流量进行量化细胞仪以及Ag特异性免疫反应的有效性这些菌株将在体内进行测试。这些研究将提供有关 CD4+ T细胞识别的AG的性质类似地对病原体反应适应吞噬体中的生命。在AIM 4中，AGS的功能重要性在目标1和2中确定的将通过测试纯化的AGS确定其通过有毒的能力刺激保护性免疫免受挑战的能力沙门氏菌。确定的保护性AG将是出色的候选人人类亚基疫苗和细胞免疫标记的成分。