BASIS OF DETERMINANT RECOGNITION BY THE IMMUNE SYSTEM

这项建议的长期目标是了解以下因素 对脆弱类杆菌的毒力和致病性有贡献， 腹内化脓性肠炎最主要的厌氧菌 人类的盆腔炎。因为这需要遗传和 对毒力因素的生理学分析，我们的方法一直是 开发新的遗传系统用于脆弱芽孢杆菌以鉴定 潜在的毒力决定因素。 我们将重点放在脆弱芽孢杆菌的耐氧性上，认为这是一个重要的因素。 生物体在含氧组织中生存的能力。我们将分析 一组脆弱芽孢杆菌蛋白，仅在 氧气的存在。我们将研究这些化合物的合成控制。 氧反应蛋白(ORPs)和试图识别全局和基因 特定的监管机构。我们还将研究关闭的过程 大多数脆弱芽孢杆菌蛋白通常是在厌氧菌发生时产生的 当生长中的细胞受到氧气的挑战时。我们将继续我们的 脆弱芽孢杆菌超氧化物歧化酶的研究及其作用 在脆弱芽孢杆菌体内和体外存活。 既然我们已经确定了脆弱芽孢杆菌的重要作用 神经氨酸酶对脆弱芽孢杆菌体内生长能力的影响 系统，我们将集中在定义NanH的控制区 了解结构基因及其表达是如何被调控的。 我们将使用TnPhoA系统的改编版本， 大肠杆菌鉴定出口蛋白，以研究表面蛋白 脆性假单胞菌。由于许多细胞被膜蛋白在细菌中发挥作用 致病性，我们将使用TnCef来鉴定毒力决定因素 脆弱芽孢杆菌表面蛋白或出口蛋白。基因突变的突变体 潜在的毒力因子将被测试它们在 脆弱芽孢杆菌感染的两个模型系统，大鼠肉芽肿囊，和 培养中的CHO或Monika P15动物细胞。 我们将寻找只有在细菌感染后才表达的脆弱杆菌基因。 细菌在体内生长。这些基因很可能发挥重要的作用 在建立和维持脆弱芽孢杆菌感染中的作用。 进一步明确脆弱芽孢杆菌感染大鼠的初始步骤 ，我们将在以下位置对感染的眼袋进行组织学分析 感染后早期。我们将确定 在厌氧菌建立过程中感染脆弱芽孢杆菌细胞 细菌生长所需的环境。

The long term objective of this proposal is to understand the factors that contribute to the virulence and pathogenicity of Bacteroides fragilis, the most important anaerobic pathogen in suppurative intra-abdominal and pelvic infections in human beings. Since this requires a genetic and physiological analysis of the virulence factors, our approach has been to develop new genetic systems for use in B. fragilis in order to identify potential virulence determinants. We are focusing on the aerotolerance of B. fragilis as an important factor in the organisms' ability to survive in oxygenated tissue. We will analyze a set of B. fragilis proteins that are highly expressed only in the presence of oxygen. We will study the control of the synthesis of these oxygen response proteins (ORPs) and attempt to identify global and gene specific regulators. We will also study the process of the shut-off of most B. fragilis proteins normally made during anaerobiosis that occurs when the growing cells are challenged with oxygen. We will continue our studies on the superoxide dismutase of B. fragilis and determine its role in B.fragilis survival in vitro and in vivo. Since we have determined an important role for the B.fragilis neuraminidase in the ability of B.fragilis to grow in two in vivo test systems, we will concentrate on defining the control region of the nanH structural gene and in understanding how its expression is regulated. We will use an adaptation of the TnphoA system that has been used in E.coli to identify exported proteins, in order to study surface proteins of B. fragilis. Since many cell envelope proteins play a role in bacterial pathogenicity, we will use TnCef to identify virulence determinants among B. fragilis surface or exported proteins. Mutants with alterations in potential virulence factors will be tested for their ability to grow in two model systems of B. fragilis infection, the rat granuloma pouch, and CHO or Monika P15 animal cells in culture. We will search for B. fragilis genes that are only expressed when the bacteria are growing in vivo. These genes are likely to play an important role in the establishment and maintenance of B. fragilis infections. To further define the initial steps in B.fragilis infection of the rat pouch, we will perform a histological analysis of the infected pouch at early times after infection. We will determine the location of the infecting B. fragilis cells during the establishment of the anaerobic environment that is required for bacterial growth.