Molecular mechanisms of Francisella tularensis pathogenesis & immunity

图拉氏弗朗西斯杆菌是一种高度传染性的革兰氏阴性球菌，它能引起 人畜共患病图拉热症是一种A类药物。了解F. 为了抗击可能的威胁，土拉氏病是显而易见的。图拉热症的一个特征是 细菌在哺乳动物宿主中生长，然后开始保护性细胞介导的免疫反应。 哺乳动物宿主具有多种抗菌效应器功能。因此，图拉氏针叶蝉 已经进化出了颠覆宿主防御的机制。令人惊讶的是，这种小细菌可以感染它的 宿主通过各种不同的感染途径，每一种途径都涉及不同的宿主组织部位，具有极大的 不同的微环境。鉴于图拉氏丝虫如此成功地通过多个组织感染其宿主 我们的假设是，除了一般生存和生长所需的一组核心基因外， 在体内，图拉氏丝虫拥有特定组织或微核所需的额外基因。因此，我们的 首要目标是确定图拉氏丝虫中新的核心和组织特异性毒力因子。在第一个 目的，我们将鉴定组织特异性(如肺、脾和皮肤特异性)图拉氏杆菌毒力因子。 我们成熟的基于微阵列的阴性选择方法，在鼻腔、腹膜内 以及皮内接种途径。在第二和第三个目标中，我们将验证组织特异性 新的毒力因子及其在小鼠感染和感染模型中的分子机制 体外组织培养试验。 该项目与该计划中的其他Francisella项目具有协同作用，因为它将使我们能够 直接比较马库斯·霍维茨博士实验室获得的遗传和蛋白质组分析结果 利用图拉氏华山菌亚种。Tularens、LVS和F.novicida与我们体内的阴性选择结果。 由于我们将在体内和体外检测中使用相同的转座子突变体库，接下来我们的 基于微阵列的快速检测方法，我们将识别与之相互作用的新的弗朗西斯氏菌因子 宿主蛋白质以一种极其有效的方式。

Francisella tularensis is a highly infectious gram-negative coccobacillus that causes the zoonosis tularemia and is a Category A agent. The need for understanding the molecular basis for F. tularensis disease in order to combat possible threats is evident. A hallmark of tularemia is the ability of the bacterium to grow in mammalian hosts before the onset of a protective cell-mediated immune response. Mammalian hosts are endowed with numerous antimicrobial effector functions. Accordingly, F. tularensis has evolved mechanisms to subvert host defenses. It is very striking that this small bacterium can infect its host via a variety of different infection routes, each of which involves a different host tissue site with a vastly different microenvironment. Given that F. tularensis is so successful at infecting its host via multiple tissue sites, our hypothesis is that in addition to a core set of genes that are needed for general survival and growth in vivo, F. tularensis possess additional genes that are required in specific tissues or microniches. Thus, our overarching goal is to identify novel core and tissue-specific virulence factors in F. tularensis. In the first aim, we will identify tissue-specific (e.g. lung-, spleen, and skin-specific) F. tularensis virulence factors using our well-established microarray-based negative selection methodology following intranasal, intraperitoneal and intradermal routes of inoculation. In the second and third aims, we will validate the tissue-specificity of novel virulence factors and characterize the molecular mechanisms in our mouse models of infection and in vitro in tissue culture assays. This project is synergistic with the other Francisella project in the Program in that it will allow us to directly compare the results of genetic and proteomic analyses obtained by Dr. Marcus Horwitz's laboratory utilizing F. tularensis subsp. tularensis, the LVS and F. novicida with our in vivo negative selection results. Since we will be using the same transposon mutant library for our in vivo and in vitro assays, followed by our very rapid microarray-based detection method, we will identify novel Francisella factors that interact with host proteins in an extremely efficient manner.