Adjuvants' mechanisms

描述(申请人提供)：基于蛋白质的受体配体相互作用被普遍认为是免疫激活的起始点。然而，我是否适用于固体结构的免疫识别是值得怀疑的。这个问题在疫苗设计中特别相关，因为一些最著名的佐剂是固体晶体，如明矾和尿酸一钠。颗粒抗原与抗原提呈细胞(APC)的结合是免疫激活的关键步骤。已证明尿酸和明矾晶体是有效的佐剂，可启动强健的适应性免疫反应。然而，激活的机制尚不清楚。使用原子力显微镜作为实时单细胞激活分析的工具，我们收集到的证据表明，尿酸和明矾晶体可以直接与细胞膜结合，其作用力远远强于基于蛋白质的细胞接触。颗粒物质的结合激活树突状细胞(DC)中的Syk激酶依赖的信号转导。这些观察结果提出了一种机制，即固体结构可以通过膜脂改变触发免疫细胞激活，而不需要特定的细胞表面受体，并提出了晶体相关炎症和佐剂的可检验假说。在这个提案中，我们扩展了研究结果，以研究涉及的信号机制，特别是细胞表面脂质分选和下游信号转导之间的关联，晶体介导的免疫激活的关键步骤，以及这种机制如何影响抗原递呈。这项工作的结果将影响疫苗的开发和我们对晶体相关疾病的理解。 与公共健康相关：我们建议在这里研究免疫细胞膜中的脂质如何感知晶体和珠子等固体结构。这是一个与疫苗开发、植入物研究、药物输送和对空气污染的炎症反应有关的重要课题。具体地说，我们将研究在响应这些固体结构时，在脂质结合之后发生了什么类型的信号事件，以及它们是如何影响免疫结果的。

DESCRIPTION (provided by applicant): Protein based receptor ligand interactions are universally regarded as the initiating point of immune activation. However, it is questionable if i is applicable to immune recognition of solid structures. This issue is particularly relevant in vaccine design as some of the best known adjuvants are solid crystals, such as alum and monosodium urate. Binding of particulate antigens by antigen presenting cells (APC) is a critical step in immune activation. It has been demonstrated that uric acid and alum crystals are potent adjuvants, initiating a robust adaptive immune response. However, the mechanisms of activation are unknown. Using atomic force microscopy as a tool for real time single cell activation analysis, we have collected evidence that uric acid and alum crystals can directly engage cellular membranes, with a force substantially stronger than protein based cellular contacts. Binding of particulate substances activates Syk kinase-dependent signaling in dendritic cells (DCs). These observations suggest a mechanism whereby immune cell activation can be triggered by solid structures via membrane lipid alteration without the requirement for specific cell surface receptors, and a testable hypothesis for crystal-associated inflammation and adjuvanticity. In this proposal, we extend the findings to study the signaling mechanisms involved, particularly the association between cell surface lipid sorting and downstream signal transduction, critical steps in crystal mediated immune activation, as well as how this mechanism affects antigen presentation. The outcome of this work will impact vaccine development and our understanding of crystal related diseases. PUBLIC HEALTH RELEVANCE: We propose here to study how lipids in the immune cell membrane can sense solid structures like crystals and beads. This is an important topic related to vaccine development, implant research, drug delivery and inflammatory responses to air pollution. Specifically, we will study what type of signaling events follow lipid binding in respone to these solid structures and how they impact immune outcomes.