Characterisation of Galleria mellonella innate immune response to Mycobacterium tuberculosis infection

大蜡蛾（Galleria mellonella， GM）是一种危害蜂巢的害虫。然而，已经发现转基因毛虫可以在实验室中被人类细菌病原体感染。这种转基因“感染模型”可以用来理解病原体如何在人类中引起疾病，这得益于昆虫和人类免疫系统之间的许多相似之处。转基因现在越来越多地被用作动物感染模型的替代品。然而，更广泛地使用基于转基因的感染模型的一个主要限制是缺乏可用于表征转基因免疫系统的试剂。这种转基因试剂的可用性将导致更多地采用基于转基因的感染模型，并将进一步减少在研究中使用动物。在这项令人兴奋的研究中，我将首次生成能够区分转基因中发现的六种血细胞亚型（被认为相当于人类白细胞群）的试剂。这些试剂将用于表征转基因结核分枝杆菌（MTB）感染模型中的免疫反应。结核分枝杆菌是人类结核病的病因，在covid大流行之前，结核病是全球因感染而死亡的主要原因。为了实现世卫组织到2035年结束结核病流行的目标，迫切需要替代感染模式，如转基因。在获得这个奖学金之前的工作中，我建立了一个GM-MTB感染模型。与最广泛使用的小鼠模型不同，肉芽肿——人类结核病的标志——是在转基因中产生的。我们知道它们的形成需要血细胞。然而，我们不知道是只需要少数还是全部六种亚型的转基因血细胞。了解涉及哪些亚型将有助于更好地了解昆虫免疫，特别是转基因对MTB的反应所涉及的血细胞亚型。此外，我将分析哪些基因在感染结核分枝杆菌的转基因毛虫中表达，以便与人类研究进行直接比较。该项目的结果将是产生试剂和方法，以便更好地了解转基因免疫，特别是幼虫对结核分枝杆菌感染的反应，以及它与人类对结核分枝杆菌的免疫反应有多接近。所有试剂、方法和结果都将公开。这个项目的成功完成不仅会使转基因-结核分枝杆菌感染模型得到更广泛的应用，而且还会使目前正在使用的其他转基因感染模型（其中超过65种）得到更广泛的应用。

The Greater wax moth (Galleria mellonella, GM) is an insect pest of honeybee hives. However, it has been found that the caterpillar of GM can be infected in the laboratory by human bacterial pathogens. Such GM "infection models" can be used to understand how pathogens cause diseases in humans, helped by the many similarities between the insect and human immune system. GM are now being increasingly being used as an alternative to animal infection models. However, a major limitation to the more widespread use of GM-based infection models is the lack of reagents that can be used to characterise the GM immune system. Availability of such GM reagents would lead to a greater uptake of GM-based infection models and will further reduce the use of animals in research.In this exciting Fellowship, I will generate reagents, which for the first time, can distinguish the six sub-types of haemocytes (considered equivalent to white blood cells populations in humans) found in GM. These reagents will be used to characterise the immune response in a GM-Mycobacterium tuberculosis (MTB) infection model. MTB is the cause of human tuberculosis (TB) which, until the covid pandemic, was the leading worldwide cause of death due to infection. To meet the WHO goal of ending the TB epidemic by 2035, alternative infection models - like GM are urgently needed. In the work leading up to this Fellowship, I have established a GM-MTB infection model. Unlike the most widely used mouse model, granulomas - the hallmark of human TB - are produced in GM. We know that haemocytes are required for their formation. However, we do not know if only a select few or all six sub-types of GM haemocytes are needed. Knowing which sub-types are involved will enable a greater understanding of insect immunity and, in particular, the haemocyte sub-types that are involved in the response of GM to MTB. In addition, I will analyse which genes are expressed in GM caterpillars infected with MTB, allowing direct comparison with human studies. The outcome of this project will be the generation of reagents and methods that will allow a greater understanding of GM immunity, in particular, the response of larvae to MTB infection, and how close it is to the human immune response to MTB. All reagents, methods and results will be made publicly available. A successful conclusion to this project will result in a greater uptake of not only the GM-MTB infection model, but also in other GM infection models (of which there are over 65) that are currently in use.