Development of a non lethal sampling method to monitor immune response and disease progression in salmonid fish.

英国和世界各地的养鱼业面临着来自病毒和细菌的严重经济威胁，这些病毒和细菌会导致宝贵牲畜的暴发和损失。经常给鱼接种疫苗和免疫刺激剂以防止这些暴发。需要持续的研究来验证新产品是否有效。为了做到这一点，世界各地的研究通常是通过大量动物实验感染病原体来进行的。然后，将用这种物质处理的鱼群的死亡率与未处理的鱼群的死亡率进行比较。其他研究人员专注于了解鱼的免疫系统是如何工作的，以及它是如何对抗细菌和病毒的入侵的。为此，进行了实验，通过实验感染一组鱼的病毒或细菌病原体，然后定期杀死至少5条鱼并进行分析。就使用的动物数量而言，这两种方法都非常昂贵，我们建议从这个为期两年的项目中进行的工作中减少这一成本。我们建议在感染过程中重复采集少量血液，而不是定期捕杀鱼类，而不是伤害鱼类。本实验设计所需的动物数量仅为传统抽样方法所需鱼类数量的20%。此外，在感染过程中跟踪同一条鱼将有助于更好地了解鱼引起的免疫反应，以及这种反应的结果，即死亡或存活。该项目的一部分将致力于改进分析方法。由于在感染过程中只需重复采集少量血液，因此需要新的方法来测量和描述免疫反应。其中一些工具包括抗体，特别是识别单个免疫分子的抗体，关于鱼类免疫基因的信息，以及可以在体外培养的永生鱼类细胞的存在。这些方法将适用于收集的少量血液，并将用于了解哪些血细胞和血清分子在对抗病原体方面具有重要作用。细胞类型、涉及的分子、病原体类型和感染的最终结果之间的关系对于预测感染的严重程度、确定要使用的适当免疫刺激剂和改进现有的鱼类疫苗将非常重要。

Fish farming in the UK and around the world faces serious economical threats from viruses and bacteria causing outbreaks and loss of valuable livestock. Vaccines and immunostimulants are often administered to fish to prevent these outbreaks. Continuous research is required to verify whether new products are effective. In order to do so, research worldwide is routinely carried out whereby large groups of animals are experimentally infected with a pathogen. The level of mortalities in groups of fish treated with such substances are then compared with a group of untreated fish. Other researchers have focused on understanding how the fish immune system works and how it combats invasion by bacteria and viruses. For this, experiments are undertaken whereby a group of fish is experimentally infected with viral or bacterial pathogens, then at regular intervals, at least 5 fish are killed and analysed. Both methods are very costly in terms of the number of animals used, and we propose to reduce this from the work carried out during this 2 year project. Instead of killing fish at regular intervals, we propose to take small volumes of blood repeatedly during the course of the infection without harming the fish. The number of animals required for this experiment design represents only 20 % of the number of fish required using traditional sampling methods. In addition, following the same fish during the course of the infection will allow a better understanding of the immune response elicited by the fish, and the outcome of this response i.e. death or survival. Part of the project will be dedicated to improving the analysis method. Because only a small volume of blood is repeatedly sampled over the course of the infection, novel methods are required to measure and describe the immune response. Some of the tools to be includes are antibodies, specifically recognise individual immune molecules, information on fish immune genes and the existence of immortal fish cells that can be cultivated in vitro. These methods will be adapted for use with the small volumes of blood collected and will be used to understand which blood cells, and serum molecules are important in combating the pathogen. The relation between the cell types, the molecules involved, the type of pathogen and the final outcome of the infection will be very important in predicting the severity of infection, determining the appropriate immunostimulant to be used and improving existing fish vaccines.