Immunity to Intracellular Pathogens

对细胞内病原体的免疫力

• 批准号: 6851509
• 负责人: EMIL Raphael UNANUE
• 金额: $ 38.25万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-12-01 至 2009-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6851509
• 关键词: Listeria; Listeria infections; SCID mouse; apoptosis; bacteria infection mechanism; bacterial cytopathogenic effect; bacterial proteins; bactericidal immunity; cell population study; histology; intracellular; laboratory mouse; leukocyte activation /transformation; lymphocyte; pore forming protein; proteolysis; recombinant proteins; transfection

DESCRIPTION (provided by applicant): This proposal examines infection with the facultative intracellular pathogen Listeria monocytogenes (LM), focusing on the early stage when LM is multiplying in tissues at a high exponential rate. During this period, precisely by the 48th hour, there is extensive lymphocyte death by apoptosis in lymphoid organs. The death is caused by the LM virulent pore forming protein Listeriolysin O (LLO). This proposal is based on three observations, the finding of extensive lymphocyte apoptosis in infective foci, our finding ex vivo and in vivo, that LLO is apoptogenic to lymphocytes; and observations indicating that the lymphocyte death stage may be linked to a period of lower resistance. The lower resistance became evident when SCID mice were found to handle the exponential growth phase better than normal mice. Pointedly, SCID mice injected with lymphocytes at the same time of infection, reverted to the pattern seen in normal mice, with higher LM burden. The plans include examining the molecular basis of LLO action on cells, to in vivo analysis of how LLO may be acting, plus an evaluation of the changes that take place in lymphoid organs at the time of the apoptotic phase. Accordingly, how LLO induces apoptotic death of lymphocytes is examined in detail. Preliminary evidence indicates that LLO initiates an intracellular proteolytic pathway that results in the death program. Experiments are planned to determine the nature of this pathway. Having a better understanding and pinpointing critical molecules in the death pathway may allow the infection to be modulated by targeting such molecules in a number of ways. Another important issue to examine is whether lymphocytes vary in their susceptibility to LLO apoptosis depending on their set and/or activation states: this issue is tackled by both in vivo and ex vivo experiments with purified cells. A LM that expresses LLO as a membrane protein is being engineered, in order to explore whether it is extracellular LLO that causes the lymphocyte death. The proposal includes a number of different approaches in order to determine whether lymphocyte apoptosis modulates in a negative way the infectious process. In summary, listeriosis is a powerful system to examine the relevance of lymphocyte death to the outcome of an infectious disease.

描述（由申请人提供）：该提案检查了辅助细胞内病原体单核细胞增生李斯特氏菌（LM）的感染，重点是以高指数率在组织中繁殖的早期阶段。在此期间，正好在第48小时的时间里，淋巴机构中凋亡会大量淋巴细胞死亡。 死亡是由LM毒孔形成蛋白李斯特氏蛋白O（LLO）引起的。 该建议基于三个观察结果，即在感染灶，我们的离体和体内发现广泛的淋巴细胞凋亡的发现，即LLO对淋巴细胞具有凋亡。并观察表明淋巴细胞死亡阶段可能与较低耐药性时期有关。当发现SCID小鼠比正常小鼠更好地处理指数生长阶段时，较低的电阻变得明显。明确的是，SCID小鼠在同一感染时注射淋巴细胞，恢复为正常小鼠中的模式，LM负担更高。 该计划包括检查LLO对细胞的分子基础，以对LLO的作用进行体内分析，以及评估凋亡阶段时淋巴机器人中发生的变化。因此，详细研究了LLO如何诱导淋巴细胞的凋亡死亡。 初步证据表明，LLO启动了导致死亡计划的细胞内蛋白水解途径。计划确定该途径的性质。在死亡途径中具有更好的理解并指出了临界分子，可以通过多种方式靶向此类分子来调节感染。要检查的另一个重要问题是，淋巴细胞在其对LLO凋亡的敏感性方面是否取决于其集合和/或激活状态：该问题均由纯化细胞的体内和离体实验解决。一种表达LLO为膜蛋白的LM正在设计为膜蛋白，以探索是否是淋巴细胞死亡的细胞外LLO。该提案包括多种不同的方法，以确定淋巴细胞凋亡是否以阴性方式调节感染过程。总而言之，李斯特氏病是一个强大的系统，可检验淋巴细胞死亡与传染病结果的相关性。