Integrins, non-canonical autophagy and GC B cell response to viruses

项目摘要/摘要 更好地了解由各种类型的抗原触发的免疫信号机制对于 针对当前和新出现的病原体开发更有效的疫苗。我们的长期目标是 了解B细胞如何整合来自抗原及其环境的信号以产生有效的免疫 对抗病原体，同时保持对自体抗原的耐受性。 本申请的目的是确定一系列黏附分子， 病毒整合素和自噬蛋白调节生发中心(GC)B细胞对病毒抗原的处理及其方式 这影响了对多种流感病毒株的有效免疫力的发展。在出版的作品中，我们有 研究表明，来自av家族的avb3异源二聚体与自噬途径的组件结合，以限制 B细胞中的TLR信号转导。在目前的研究中，我们发现，av-自噬途径限制了GC B细胞对 含有TLR配体的病毒抗原。结果，在B细胞上缺乏av的av-CD19小鼠表现出关键字的增加 GC介导的抗体反应的特点，如抗体的亲和力成熟，记忆B的产生 在病毒样颗粒或流感病毒免疫后，细胞和长寿的浆细胞。此外，这些 小鼠在接种一种流感病毒株后产生更多的交叉反应抗体 紧张。Av-cd19小鼠也会随着年龄的增长而产生更多的自身抗体，我们认为av介导的 调节TLR信号是一种限制B细胞对自身抗原过度反应的机制。我们的中央 这项授权的假设是，av-自噬途径也调节内体对抗原的处理。 含有TLR配体，来源于病原体，并限制这些抗原对GC B细胞的激活。因此， 从GC B细胞中去除这种控制，增强GC B细胞TLR信号和GC介导的 针对病原体的亲和力和广度增加的抗体。我们支持这项提议的理由是 了解病毒抗原调节GC B细胞激活的新途径将使我们能够开发出更多 针对快速演变的病毒产生有效免疫力所需的疫苗接种策略，如 流行性感冒。在这项研究中，我们建议：(1)准确地确定自噬蛋白是如何参与GC B细胞的 对病毒抗原的反应；以及(2)确定移除av-自噬途径是否能带来更好的交叉 对流感病毒株的保护性免疫；以及(3)确定病原体如何获得含有TLR的抗原 配体被GC B细胞处理，以及av-自噬途径如何改变这一过程。 这项拟议的工作意义重大，因为它解决了病原体激活GC B细胞的机制 衍生抗原，这是相对未被探索的，但对于了解开发更好的疫苗是必不可少的。 此外，在这些研究的基础上，av拮抗剂可以用于设计疫苗佐剂，提供长期的 对多种流感病毒株的长期保护。我们的方法是创新的，因为我们使用了 增强B细胞TLR信号的独特小鼠模型，以研究一种新的TLR-av-自噬途径。

Project Summary/Abstract A better understanding of immune signaling mechanisms triggered by various types of antigens is critical for development of more effective vaccines against current and emerging pathogens. Our long-term goal is to understand how B cells integrate signals from antigens and their environment to produce effective immunity against pathogens while maintaining tolerance to self-derived antigens. The objective in this application is to determine the mechanisms by which a family of adhesion molecules, av integrins and autophagy proteins regulate germinal center (GC) B cell processing of viral antigens and how that impacts development of effective immunity to multiple Influenza virus strains. In published work we have shown that avb3 heterodimer from the av family, combines with components of the autophagy pathway, to limit TLR signaling in B cells. In current studies we find that, av-autophagy pathway limits GC B cells response to viral antigens containing TLR ligands. As a result, av-CD19 mice lacking av on B cells show increase in key features of GC-mediated antibody response such as affinity maturation of antibodies, generation of memory B cells and long-lived plasma cells, upon immunization with virus like particles or Influenza virus. Moreover, these mice develop increased cross-reactive antibodies against influenza virus strains after immunization with one strain. av-CD19 mice also develop increased autoantibodies with age, and we propose that av-mediated regulation of TLR signaling is a mechanism that limits excessive B cell responses to self-antigens. Our central hypothesis for this grant, is that the av-autophagy pathway also regulates endosomal processing of antigens containing TLR ligands, derived from pathogens, and limits GC B cell activation by these antigens. Therefore, removal of this control from GC B cells, enhances GC B cell TLR signaling and GC-mediated generation of antibodies with increased affinity and breadth against pathogens. Our rationale for this proposal is that a better understanding of new pathways regulating GC B cell activation by viral antigens will allow us to develop much needed vaccination strategies for generation of effective immunity against rapidly evolving viruses such as Influenza. In this grant we propose to: (1) Determine exactly how autophagy proteins are involved in GC B cell response to viral antigens; and (2) Determine whether removal of av-autophagy pathway can lead to better cross protective immunity to influenza virus strains; and (3) Determine how pathogen derived antigens containing TLR ligands get processed by GC B cells and how av-autophagy pathway alter this process. The proposed work is significant because it addresses the mechanisms of GC B cell activation by pathogen derived antigens, which is relatively unexplored but essential to understand for developing better vaccines. Moreover, based on these studies, av antagonists could be used to design vaccine adjuvants that provide long- term protection against wide variety of Influenza virus strains. Our approach is innovative as we are using a unique mouse model of enhanced B cell TLR signaling to investigate a novel TLR-av-autophagy pathway.