GENE EXPRESSION IN BRUCELLA-INFECTED MACROPHAGES

描述(申请人提供)：布鲁氏菌是引起动物和人类布鲁氏菌病的细胞内兼性细菌。有四种布鲁氏菌对人类有致病性，被列为NIAID B类优先病原体。然而，目前还没有安全有效的布鲁氏菌疫苗可供人类使用，布鲁氏菌在宿主组织中成功复制的基本机制尚不清楚。羊瘟杆菌、猪瘟杆菌和流产杆菌对人类的毒力最强。脂多糖(LPS)中O侧链的存在区分了光滑的强毒布鲁氏菌和粗毒或弱毒的布鲁氏菌。布鲁氏菌O-侧链已被证明能诱导保护性细胞免疫。光滑的布鲁氏菌在宿主巨噬细胞内感染和复制，而粗糙株感染和复制的时间有限。我们建议使用高通量DNA微阵列技术来研究小鼠巨噬细胞对布鲁氏菌光滑株和粗株感染反应时间过程中的差异和协调基因表达。将分析布鲁氏菌O侧链在刺激巨噬细胞特异性基因反应中的作用。DNA微阵列实验检测到的基因表达谱将通过实时荧光RT-PCR进行确认。这项研究将极大地帮助理解宿主抵抗强毒和减毒布鲁氏菌株感染的遗传基础，并可能开发新的治疗和预防感染的策略。

DESCRIPTION (provided by applicant): Brucella are intracellular facultative bacteria causing brucellosis in animals and humans. Four Brucella species are pathogenic to humans and classified as NIAID category B priority pathogens. However, no safe and effective Brucella vaccine is available for human use and the basic mechanisms by which Brucella successfully replicate intracellularly in host tissues remains unclear. B. melitensis, B. suis, and B. abortus are the most virulent to humans. The presence of the O-side chain in lipopolysaccharide (LPS) distinguishes smooth virulent Brucella strains from rough attenuated or avirulent strains. Brucella O-side chain has been shown to induce protective cell mediated immunity. Smooth Brucella infect and replicate within host macrophages whereas rough strains infect and replicate for a limited time. We propose to use high throughput DNA microarray technology to study differential and coordinated gene expression in the time course of murine macrophage responses to infection with smooth and rough Brucella strains. The role of Brucella O-side chain in stimulation of specific macrophage gene responses will be analyzed. The gene expression profiles detected by DNA microarray experiments will be confirmed by real-time RT-PCR. The proposed research will greatly help in understanding the genetic basis of host defenses against infection by virulent and attenuated Brucella strains and make possible development of novel strategies to treat and prevent infections.