HOST RESPONSE EFFECT ON MYCOBACTERIAL GENE EXPRESSION

描述（改编自申请人的摘要）：了解 发病机制，必须研究感兴趣的病原体在一个环境中， 诱导生存或引起疾病的基因表达 疾病，如自然宿主或动物模型。 基因表达 可以为生物体的发病机制提供线索， 包括毒力因子。 尽管宿主对病原体的免疫反应 和病原体本身通常是分开研究的， 病原体对宿主免疫机制的作用往往被忽视。 细菌调节 基因表达对环境刺激的反应。 因此， 病原体会调节其基因表达， 反应 在结核分枝杆菌的情况下， 毒力和存活机制，或宿主因子对病原体的影响 基因表达。 作为鉴定基因编码的第一步， 潜在的毒力和生存因素，建议解决 小鼠模型中分枝杆菌基因表达的问题，重点是 宿主免疫反应对该病原体基因表达的影响。 虽然分枝杆菌引起的免疫反应很多， 感染时，该建议的重点将是巨噬细胞激活。 提出了一种改进的RNA消减杂交方法， 在体内和体外通过巨噬细胞活化诱导表达。 M. 结核病基因在活化和静止组织培养中的表达 将比较巨噬细胞。 使用该系统，希望 体外巨噬细胞活化诱导的基因群 将被隔离。 还建议评估巨噬细胞的作用， 使用两种小鼠模型对体内分枝杆菌基因表达的激活 其在巨噬细胞活化中缺乏或延迟， 细胞因子作用 在来自野生型和野生型的杆菌中的基因表达 将比较基因破坏的小鼠，以分离出一群基因， 是由体内巨噬细胞活化诱导的。 阳性选择 提出了一种杂交方法来鉴定基因的一个子集， 在体外和体内模型中表达。 人们希望 在这些模型系统中通常表达的基因的表征将 为M.结核病和 可能会导致关于这种病原体的能力的信息， 在免疫反应中存活下来

DESCRIPTION (Adapted from the applicant's abstract): To understand pathogenesis, one must study the pathogen of interest within an environment that induces the expression of genes necessary for survival or for causing disease, such as the natural host or an animal model. Gene expression within a host can provide clues to the pathogenesis of an organism, including virulence factors. Although host immune response to a pathogen and the pathogen itself are often studied separately, the response of the pathogen to host immune mechanisms is often neglected. Bacteria regulate gene expression in response to environmental stimuli. Thus, it is likely that a pathogen will modulate its gene expression to survive the host immune response. In the case of Mycobacterium tuberculosis, little is known about virulence and survival mechanisms, or the impact of host factors on pathogen gene expression. As a first step in the identification of genes encoding potential virulence and survival factors it is proposed to address the question of mycobacterial gene expression in murine models with a focus on the effect of the host immune response on gene expression by this pathogen. Although there are many immune responses elicited by mycobacterial infection, the focus of this proposal will be on macrophage activation. Improved RNA subtractive hybridization methodology is proposed to study gene expression induced by macrophage activation both in vivo and in vitro. M. tuberculosis gene expression in activated and resting tissue culture macrophages will be compared. Using this system it is hoped that a population of genes induced in response to macrophage activation in vitro will be isolated. It is also proposed to assess the effects of macrophage activation on mycobacterial gene expression in vivo, using two mouse models which are deficient or delayed in macrophage activation due to defects in cytokine action. Gene expression in bacilli from wild type and gene-disrupted mice will be compared, to isolate a population of genes that are induced by macrophage activation in vivo. A positive selection hybridization procedure is proposed to identify a subset of genes commonly expressed in the in vitro and in vivo models. It is hoped that characterization of the genes commonly expressed in these model systems will provide clues for the mechanisms macrophage survival of M. tuberculosis and possibly lead to information regarding the ability of this pathogen to survive the immune response.