Visualization and analysis of dendritic cell function in zebrafish

描述(申请人提供)：树突状细胞(DC)是免疫系统中的特殊细胞，是天然免疫系统和获得性免疫系统之间的重要桥梁。DC和其他先天免疫细胞通过表达不同类型的病原体识别受体来感知病原体。这些受体的激活会触发先天免疫反应，这是人体的“第一道防线”，对感染提供快速但有限的反应。然而，树突状细胞与其他免疫细胞的独特之处在于，它们能够吸收抗原并迁移到局部淋巴结，在那里它们将处理后的抗原呈递给有组织的T淋巴细胞池。这启动了免疫反应的适应性臂，这是免疫记忆和疫苗接种的基础。树突状细胞还参与其他关键过程，包括诱导耐受和肿瘤免疫监视。然而，关于DC如何执行这些功能以及它们可能如何在治疗上进行调节的许多问题仍然没有答案。使用斑马鱼作为模型系统是研究免疫系统的传统方法的一种潜在的强有力的替代。先前的研究表明，许多适应性免疫系统的基本成分，包括B和T淋巴细胞，在斑马鱼中是保守的。此外，Traver实验室最近发现了一组具有哺乳动物DC的形态和功能特征的细胞。我们建议检验这一假设，即适应性免疫反应的启动是由斑马鱼中的DC介导的，因此在鱼类和哺乳动物之间是保守的。首先，我们将改进现有的斑马鱼树突状细胞的鉴定方法，通过与哺乳动物树突状细胞的基因比较来鉴定斑马鱼树突状细胞。其次，由于斑马鱼缺乏明显的淋巴结，我们将尝试通过共聚焦成像跟踪DC的迁移以及与T细胞的相互作用来识别组织中的淋巴结样组织。最后，我们将通过在活体动物中删除斑马鱼DC并测量对自然病原体的反应来测试它们的功能。如果拟议的目标实现，我们和其他人将能够充分利用斑马鱼模型的令人兴奋的功能，包括独特的遗传工具、实时实时成像、正向基因筛查和药物筛查，这最终将使我们能够回答关于DC如何从根本上发挥作用的问题，并找到针对这些功能的新疗法。

DESCRIPTION (provided by applicant): Dendritic cells (DCs) are specialized cells of the immune system that serve as an essential bridge between the innate and adaptive immune system. DCs and other innate immune cells sense pathogens by their expression of different types of pathogen recognition receptors. Activation of these receptors triggers the innate immune response, which is the body's "first line of defense," providing a rapid, but limited response to infections. However, DCs are unique from other immune cells in their ability to take up antigen and migrate to local lymph nodes where they present processed antigen to an organized pool of T lymphocytes. This initiates the adaptive arm of the immune response, which is the basis for immunological memory and vaccination. DCs are also implicated in other critical processes, including the induction of tolerance and tumor immunosurveillance. However, many questions about how DCs perform these functions and how they may be therapeutically modulated remain unanswered. The use of zebrafish as a model system represents a potentially powerful alternative to conventional approaches of studying the immune system. Previous studies have demonstrated that many of the essential components of the adaptive immune system, including B and T lymphocytes, are conserved in zebrafish. Furthermore, the Traver laboratory has recently identified a population of cells that share hallmark morphological and functional features of mammalian DCs. We propose to test the hypothesis the initiation of the adaptive immune response is mediated by DCs in zebrafish and thus conserved between fish and mammals. First, we will improve current methods identifying zebrafish DCs through genetic comparison with mammalian DCs. Second, since zebrafish lack obvious lymph nodes, we will try to identify lymph node-like organization in tissues by tracking the migration of DCs and interaction with T cells by confocal imaging. Finally, we will test the function of zebrafish DCs by deleting them in live animals and measuring the response to natural pathogens. If the proposed aims are achieved, we and others will be able to take full advantage of exciting features of the zebrafish model, including unique genetic tools, real-time live imaging, forward genetic screens, and drug screens, which will ultimately allow us to answer questions about how DCs fundamentally work and identify new therapies to target these functions.