Innate and Adaptive Immune Responses to Lymph-Borne Infections

提供了 病毒和抗病毒疫苗通过皮肤或粘膜进入人体， 淋巴管，并运送到区域引流淋巴结（LN）。当病毒到达LN时， 阻止继续进一步沿着淋巴管，这将导致病原体进入全身 循环引起病毒血症，具有潜在的致命后果。淋巴结被认为保留和中和淋巴传播的 微生物，但机制知之甚少。LN还启动对病毒的适应性免疫应答， 感染和疫苗，因为他们招募和窝藏大量的淋巴细胞和专门的抗原呈递 细胞（APC），其引起保护性效应子应答，尤其是中和抗体。我们的理解 关于淋巴病毒如何呈递给B细胞的研究仍然很粗略。在这里，我们提出使用多光子活体 显微镜（MP-IVM）用于处理淋巴携带的荧光病毒体的时间和空间分辨可视化， LN。我们希望能从细胞和分子机制上深入了解LNs阻止细胞凋亡的机制。 病原体传播并启动适应性体液免疫。根据初步工作，我们的中心假设 指出，结内淋巴管含有专门的细胞，这些细胞非常善于捕获病毒颗粒， 将这些颗粒呈递给滤泡B细胞。将在两个具体目标中检验这一假设： 目的1将探索决定淋巴病毒在淋巴结引流和转移中命运的细胞机制。 皮下注射部位。初步的工作已经确定了专门的巨噬细胞（Mphs）在地板上， 这些细胞可以作为病毒颗粒的细胞“捕蝇纸”， 负责LN的过滤活动。我们将研究这些捕获病毒的Mph的表型和功能 （子目标1.1），并阐述其在清除和保留不同淋巴传播病毒方面的作用（子目标1.2）。我们将 还研究了LN驻留的Mphs和其他先天性白细胞的起源和命运，以及它们与肿瘤的关系。 在血液、组织和淋巴液之间不断循环的造血干细胞和祖细胞群 （次级目标1.3）。 目标2.将分析滤泡B细胞在何处以及如何暴露于淋巴病毒并对其作出反应。我们将 检查水泡性口炎病毒（VSV）诱导早期T非依赖性和晚期T非依赖性的连续步骤， LN中的T依赖性体液免疫。Subaim 2.1将检验SCS中的Mphs作为早期APC起作用的假设 对于B细胞。Subaim 2.2将分析T细胞活化和B：T相互作用以及生发中心对病毒的反应。 挑战.最后，子目标2.3将探索聚合物纳米颗粒可以被设计成模拟 入侵病毒，并为未来疫苗的递送提供有效和通用的免疫刺激平台。

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.