Alum's adjuvanticity

描述（由申请人提供）：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，它是否适用于实体结构的免疫识别是值得怀疑的。抗原呈递细胞（APC）结合颗粒抗原是免疫激活的关键步骤。以前，我们证明尿酸晶体是有效的佐剂，启动一个强大的适应性免疫反应。然而，其激活机制尚不清楚。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晶体可以直接接触细胞膜，特别是胆固醇成分，其力比基于蛋白质的细胞接触强得多。颗粒物质的结合激活树突状细胞中Syk激酶依赖的信号传导。这些观察结果提示了一种机制，即免疫细胞激活可以通过膜脂改变由固体结构触发，而不需要特定的细胞表面受体，以及晶体相关关节病，炎症和佐剂的可验证假设。在本研究中，我们扩展了我们的工作，研究明矾如何与免疫系统相互作用，并揭示这种基于脂质的机制是否适用于明矾的佐剂性。我们还将研究细胞表面脂质分选与Nalp3炎性体活化之间的关系，Nalp3炎性体活化是尿酸晶体介导的细胞活化的关键步骤。我们将进一步研究一组与炎性小体调节无关的免疫激活事件，以建立明矾免疫调节能力的完整图景。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。

DESCRIPTION (provided by applicant): Protein based receptor ligand interactions are universally regarded as the initiating point of immune activation. However, it is questionable if it is applicable to immune recognition of solid structures. Binding of particulate antigens by antigen presenting cells (APC) is a critical step in immune activation. Previously, we demonstrated that uric acid 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 crystals can directly engage cellular membranes, particularly the cholesterol components, 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 arthropathies, inflammation and adjuvanticity. In this proposal, we extend our work to study how alum interacts with the immune system and to reveal if such a lipid based mechanism is applicable in alum's adjuvanticity. We will also study the association between cell surface lipid sorting and Nalp3 inflammasome activation, a critical step in uric acid crystal mediated cell activation. We will further study a set of immune activation events unrelated to inflammasome regulation in order to establish a complete picture of alum's immune regulating capacities. The outcome of this work will impact vaccine development and our understanding of crystal related diseases. PUBLIC HEALTH RELEVANCE: This project deals with the basic mechanism for the immune recognition of alum. It has high relevance in the vaccine development and crystal related diseases. Its outcomes will lead to better understanding of the immune system and suggest new methods for population based immunizations.