Immunity to Bacillus anthracis: Spore-Host Interactions

描述(由申请人提供)： 该计划项目的总体目标是充分了解炭疽芽孢杆菌孢子-宿主相互作用的机制，以促进炭疽病预防、干预和诊断程序的设计和开发。我们将确定糖蛋白和其他孢子壳决定因素的详细化学结构，并研究它们作为炭疽杆菌孢子特异性新靶标用于炭疽病防治的可能性。外孢子菌的详细组成将通过遗传和生化策略来表征。将对所有已知和有待发现的外孢子菌成分进行单独突变。外孢子菌的碳水化合物成分的结构将使用各种遗传、化学和光谱方法来确定。小鼠模型将被用来确定孢子通过呼吸道、胃肠道、皮肤和血液路线进入和通过的细胞路径。通过基因打靶使先天免疫系统和获得性免疫系统的选定基因失活的小鼠将被用来确定宿主中未萌发孢子的免疫病理和免疫逃避机制。野生型和突变型孢子将被用来确定这些成分在哺乳动物宿主中的孢子完整性、孢子萌发和存活中的作用。我们将使用孢子、重组外孢子菌成分和将碳水化合物定义为这些受体的配体来分离和鉴定宿主细胞上的孢子受体。 此外，该项目还将涉及在我们结构研究的基础上设计的碳水化合物-蛋白质结合物和新糖蛋白的构建。除了克隆和表达重组的外孢子菌蛋白外，这些构建物还将用于增强对炭疽杆菌外孢子体上的糖共轭的免疫反应，并有助于开发新的疫苗或干预策略，以优化特定的保护性一次和二次免疫反应，并可能导致阻止孢子进入宿主的新策略。我们的总体策略不同于目前使用的策略，该策略旨在诱导宿主在孢子入侵和萌发后对炭疽杆菌繁殖体所阐述的毒素产生保护性免疫。我们将能够确定在建立感染点和营养细胞生长之前快速灭活孢子的潜在机制。这种性质的治疗药物将是对目前推荐的抗生素方案的主要补充，或者对于具有多药耐药性的炭疽杆菌菌株来说，这种药物将产生更多的毒素用作生物武器。

DESCRIPTION (provided by applicant): The overall objective of this program project is to provide sufficient understanding of the mechanisms of Bacillus anthracis spore-host interactions to facilitate the design and development of preventive, interventive and diagnostic procedures for the disease Anthrax. We will determine the detailed chemical structure of glycoproteins and other spore coat determinants and investigate the possibility that they can be used as new B. anthracis spore-specific targets for anthrax prevention and treatment. The detailed composition of the exosporium will be characterized by genetic and biochemical strategies. Individual mutations of all known, and to be discovered, exosporium components will be made. The structure of the carbohydrate components of the exosporium will be determined using a variety of genetic, chemical and spectroscopic methods. A mouse model will be used to identify the cellular pathways of spore entry and passage via the airways, gastrointestinal, cutaneous, and blood routes. Mice in which selected genes of the innate and adaptive immune system have been inactivated by gene-targeting will be used to define mechanisms of immunopathology and immune evasion of the ungerminated spores in the host. Wild type and mutant spores will be used to determine the role of these components in spore integrity, spore germination and survival in a mammalian host. We will isolate and characterize spore-receptors on host cells using spores, recombinant exosporium components and defined carbohydrates as ligands for these receptors. In addition, this project will also involve the construction of carbohydrate-protein conjugates and neoglycoproteins designed on the basis of our structural studies. These constructs, in addition to cloned and expressed recombinant exosporium proteins, will be used to enhance immune responses to the glycoconjugates on the exosporium of B. anthracis, and assist in the development of novel vaccine or interventional strategies that will optimize specific protective primary and secondary immune responses, and may lead to new strategies for blockade of spore entry into the host. Our overall strategy differs from that currently in use which is designed to induce protective immunity to the toxins elaborated by the vegetative form of B. anthracis after spore invasion and germination in the host. We will be able to identify potential mechanisms to rapidly inactivate spores prior to establishment of infectious loci and vegetative cell outgrowth. Therapeutic drugs of this nature would be a major supplement to the current recommended antibiotic regimens or in the case of multidrug-resistant B. anthracis strains engineered to produce additional toxins for use as bioweapons.