Innate and Adaptive Immune Responses to Lymph-Borne Infections

但前提是。 通过皮肤或粘膜进入人体的病毒和抗病毒疫苗可以在附近获得 淋巴管并被输送到区域引流淋巴结(LNS)。当病毒到达LN时，它一定是 阻止沿着淋巴管道继续下去，这会将病原体引导到全身 导致病毒血症的血液循环，具有潜在的致命后果。据信，LNS可以保留和中和淋巴传播的 微生物，但对其机制知之甚少。LNS还启动对病毒的适应性免疫反应 感染和疫苗，因为它们招募和窝藏大量淋巴细胞和专门的抗原提呈 细胞(APC)，可引起保护性效应器反应，特别是中和抗体。我们的理解 淋巴传播的病毒是如何进入B细胞的，目前还很不清楚。在这里，我们准备使用多光子生命内 显微镜(MP-IVM)用于处理淋巴携带的荧光病毒粒子的时间和空间分辨可视化 移民局。我们希望获得对LNS预防的细胞和分子机制的机械性见解。 病原体传播和启动适应性体液免疫。基于初步工作，我们的中心假设 声称结内淋巴管道含有专门的细胞，这些细胞非常擅长捕获病毒颗粒，并在 将这些颗粒呈现给滤泡B细胞。这一假设将在两个具体目标中得到检验： 目的1将探索决定淋巴传播病毒在淋巴系统引流中的命运的细胞机制。 皮下注射部位。初步工作已在地板上发现了专门的巨噬细胞(MPHS) 囊下窦(SCS)和LNS的髓质，其功能可能是病毒颗粒的细胞‘苍蝇纸’，并可能是 负责LNS的过滤活动。我们将研究这些捕获病毒的MPH的表型和功能 (次级目标1.1)，并阐述它们在清除和保留不同淋巴传播病毒方面的作用(次级目标1.2)。我们会 同时调查LN-MPHS和其他先天白细胞的起源和命运，以及它们与 在血液、组织和淋巴之间持续循环的造血干/祖细胞群 (次级目标1.3)。 目标2.将分析滤泡B细胞在哪里以及如何暴露，并对淋巴传播的病毒做出反应。我们会 检查水疱性口炎病毒(VSV)诱导早期T细胞非依赖性和晚期T细胞依赖性的顺序步骤 淋巴结炎的T依赖体液免疫。Subaim 2.1将测试SCS中的MPHS作为早期APC发挥作用的假设 对于B细胞。Subaim 2.2将分析T细胞激活和B：T相互作用以及生发中心对病毒的反应 挑战。最后，SubAim 2.3将探索将聚合物纳米颗粒设计成模拟 并为未来疫苗的交付提供了一个强大和多功能的免疫刺激平台。

PROVIDED. Viruses and antiviral vaccines that enter the body through the skin or mucous membranes gain access to nearby lymph vessels and are transported to regional draining lymph nodes (LNs). When a virus arrives in a LN it must be prevented from continuing further along the lymph conduits, which would channel the pathogen into the systemic circulation causing viremia with potentially fatal consequences. LNs are believed to retain and neutralize lymph-borne micro-organisms, but the mechanisms are poorly understood. LNs also initiate adaptive immune responses to viral infections and vaccines because they recruit and harbor large numbers of lymphocytes and specialized antigenpresenting cells (APCs), which elicit protective effector responses, especially neutralizing antibodies. Our understanding of how lymph-borne viruses are presented to B cells is still very sketchy. Here, we prepose to use multi-photon intravital microscopy (MP-IVM) for time-and space-resolved visualization of the handling of lymph-borne fluorescent virions in LNs. We hope to obtain mechanistic insights into the cellular and molecular mechanisms by which LNs prevent pathogen dissemination and initiate adaptive humoral immunity. Based on preliminary work, our central hypothesis states that intranodal lymph conduits contain specialized cells that are highly adept at capturing viral particles and at presenting these particles to follicular B cells. This hypothesis will be tested in two specific aims: Aim 1 will explore the cellular mechanisms that determine the fate of lymph-borne viruses in LNs draining a subcutaneous injection site. Preliminary work has identified specialized macrophages (Mphs) in the floor of the subcaspular sinus (SCS) and the medulla of LNs that may function as a cellular 'flypaper' for viral particles and may be responsible for the filter activity of LNs. We will examine the phenotype and function of these virus-capturing Mphs (subaim 1.1) and address their role in the clearance and retention of different lymph-borne viruses (subaim 1.2). We will also investigate the origin and fate of LN-resident Mphs and other innate leukocytes and their relationship to a population of hematopoietic stem and progenitor cells that recirculate continuously between blood, tissues and lymph (subaim 1.3). Aim 2. will analyze where and how follicular B cells are exposed and respond to lymph-borne viruses. We will examine the sequential steps that are elicited by vesicular stomatitis virus (VSV) to induce early T-independent and late T-dependent humoral immunity in LNs. Subaim 2.1 will test the hypothesis that Mphs in the SCS function as early APCs for B cells. Subaim 2.2 will analyze T cell activation and B:T interactions as well as germinal center responses to viral challenge. Finally, subaim 2.3 will explore the possibility that polymeric nanoparticles could be devised to mimic invading viruses and provide a potent and versatile immuno-stimulatory platform for the delivery of future vaccines.