Development of transgenic mice to determine the role of intelectins as effectors of gastrointestinal nematode expulsion

在发展中国家，寄生于胃肠道的线虫是一个重要的人类健康问题。在英国和世界范围内，线虫对抗寄生虫药物的抵抗力越来越强，是养牛羊的一个主要问题。药物诱导的寄生虫控制的另一种方法是增强对寄生虫的自然免疫反应。寄生和过敏引起相同类型的免疫反应，这在啮齿动物中得到了广泛的研究。参与其中的细胞和信号是众所周知的，但它们改变寄生虫环境并导致其被驱逐的方式却不太清楚。我们最近的工作表明，对肠道寄生虫的免疫反应导致肠道上皮细胞产生的一种蛋白质，即肠选素-2的水平，其数量比寄生虫附近的任何其他蛋白质都要多。相反，在感染前和感染后都存在蛋白-1。我们希望验证这一假设，即智力素，特别是智力素-2，在肠道线虫的免疫驱逐中起着重要作用，同时，我们也意识到并验证了关于这种丰富蛋白质功能的其他假设。该项目旨在回答以下问题：1。蠕虫侵染部位的智力蛋白的增加是否会影响寄生虫被驱逐的速度？2. 智力素如何与其他物质（如粘液）相互作用，从而增强对寄生虫的排斥作用？3. 智力素有抗菌的特性吗？我们将利用基因工程创造三种新的小鼠系来研究智力素的作用。首先，我们将构建天然缺乏智力素-2基因的‘C57BL/6’小鼠品系的突变体，并使突变体表达智力素-2蛋白。此外，我们将在129菌株上制造“敲除”小鼠，该菌株通常表达智力素-1和智力素-2，并制造出不再能够制造智力素-2的细胞系，以及无法制造任何智力素的细胞系。通过用蠕虫感染这些小鼠，并研究蠕虫从小鼠肠道排出的速度，我们将能够确定制造智力蛋白的能力是否会影响寄生虫的排斥反应。我们还将研究纯化的智力素的特性，以了解它们如何与可能的寄生虫排斥机制相关。例如，智力素是与寄生虫结合还是与细菌结合？智力素是否与黏液结合，使黏液变厚，并通过吞噬寄生虫来帮助驱逐寄生虫？在项目结束时，我们将能够说智能性是否对寄生虫驱逐有重大贡献，并将了解更多它们的特性。如果智力素确实有助于驱逐寄生虫，那么了解它的工作原理将有助于未来设计疫苗，以提高其寄生虫驱逐效果。在过敏方面，如果确选素引起黏液增厚，那么同样可能在急性哮喘中导致危及生命的气道黏液堵塞，因此将成为一个重要的新药靶点。

Parasitic nematode worms that infest the gastrointestinal tract are an important human health concern in developing countries. Nematodes are a major problem for sheep and cattle farming in the UK, and world-wide, as they are increasingly resistant to anti-parasitic drugs. An alternative approach to drug-induced parasite control is to boost the natural immune reaction to parasites. Parasitism and allergy induce the same type of immune response, which has been studied extensively in rodents. The cells and signals involved are well known, but the way that these change the environment of the parasite and cause it to be expelled is less clear. Our recent work shows that the immune response to intestinal parasites results in levels of a protein, intelectin-2, which is produced by gut epithelial cells in greater amounts than any other protein in the vicinity of the parasite. In contrast, the protein intelectin-1 is present both before and after infection. We wish to test the hypothesis that intelectins, and particularly intelectin-2, contribute significantly to the immune expulsion of gut nematodes, while, at the same time, being aware of and testing alternative hypotheses on the function of this abundant protein. The project will aim to answer the following questions: 1. Does the increase in intelectin protein at the site of worm infestation influence the rate at which the parasite is expelled? 2. How does intelectin interact with other substances, such as mucus, in a way that could enhance rejection of parasites? 3. Do intelectins have anti-bacterial properties? We will use genetic engineering to create three new mouse lines in which to investigate the role of intelectins. Firstly, we will create a mutant of the 'C57BL/6' mouse strain, which naturally lacks the intelectin-2 gene, and make the mutant express the intelectin-2 protein. Furthermore, we will make 'knockout' mice on the 129 strain, which normally express intelectin-1 and intelectin-2, and make one line which is no longer able to make intelectin-2, and a second line that is unable to make either intelectin. By infecting these mice with worms and studying the rate of expulsion of the worms from the intestine of the mouse, we will be able to determine whether the ability to make intelectin proteins affects parasite rejection. We will also examine the properties of purified intelectins to see how they might relate to possible parasite rejection mechanisms. For example, does intelectin bind to the parasite or to bacteria? Does intelectin bind to mucus to make it thicker and help expel the parasite by engulfing it? At the end of the project, we will be in a position to say whether or not intelectins contribute significantly to parasite expulsion, and will know more of their properties. If intelectin does indeed help to expel parasites, then understanding how it works will help in the future design of vaccines to boost its parasite expelling effect. In terms of allergy, if intelectin causes mucus thickening, then it may similarly contribute to the life-threatening mucus plugging of the airways in acute asthma, and will therefore become an important new drug target.