Regulation of B cell responses to West Nile Virus Infections

这项提议的一个主要目标是阐明先天免疫感知机制的过程 规划B系细胞以产生保护性的抗西尼罗河病毒(WNV)IgM和IgG抗体。幽默 对西尼罗河病毒的免疫是保护宿主免受疾病侵袭的必要条件和充分条件，然而，早期事件 协调西尼罗河病毒最初的先天和随后的适应性抗体(Ab)反应的情况不是很好 明白了。我们将阐明树突状细胞(DC)和B细胞如何对西尼罗河病毒做出反应，以及IgM和 产生了抗西尼罗河病毒的中和抗体。我们假设DC子集的初始固有编程 规定对西尼罗河病毒的保护性抗体应答的质量和持续时间。为了研究这一假说 我们将进行以下具体目标：目标1：我们将比较德克萨斯州西尼罗河病毒的致病过程 (WN-TX)和弱毒株马达加斯加(WN-MAD)在体内感染后早期。我们建议 高致病性和低致病性西尼罗河病毒在感染、改变和编程DC的方式上有所不同。我们将量化变化 感染后早期DC亚群数量、存活率、细胞因子产生及感染情况。在项目1中，我们 将决定哪些先天免疫因素调节最初的DC反应和对西尼罗河病毒感染的易感性 通过比较野生型(WT)小鼠与C3和IPS-1 KO小鼠的DC反应和感染情况 骨髓(BM)嵌合体，其中DC已经被消融，我们将确定DC消融或 树突状细胞缺乏IPS-1、TLR-3或其他先天免疫因子会影响西尼罗河病毒感染后的早期事件。 目的2：确定快速中和免疫球蛋白M的分子和细胞需求 对西尼罗河病毒的抗体反应。边缘带(MZ)B细胞在保护IgM免疫中的作用 我们将评估MZ B细胞缺陷的CD22KO和Notch2fl/fl对WNV的IgM应答和易感性 条件性KO小鼠。DC在对包裹细菌的快速免疫球蛋白M反应中起着关键作用；使用混合 BM嵌合体，其中DC已经被消融，我们将确定DC消融或DC中没有 IPS-1、BAFF或其他先天免疫因素影响中和IgM抗体反应的发展。目标 3：我们将研究MZ B细胞是否需要免疫IgM来促进保护性IgG免疫。送货 抗原结合MZ相关树突状细胞可产生较强的抗体应答。我们将检查是否交付了西尼罗河病毒 E蛋白对MZ树突状细胞可诱导IgM和Ig G中和抗体应答，如果是，这种形式的抗原是否 分娩可用于诱导对西尼罗河病毒的保护性、灭菌性免疫。这些研究将带来新的 对如何最好地设计针对西尼罗河病毒和其他黄病毒的疫苗的见解。

A major goal of this proposal is to elucidate processes by which innate immune sensing mechanisms program B lineage cells to produce protective anti-West Nile virus (WNV) IgM and IgG antibodies. Humoral immunity to WNV is both necessary and sufficient to protect hosts from disease, however, the early events that coordinate the initial innate and subsequence adaptive antibody (Ab) responses to WNV are not well understood. We will elucidate how dendritic cells (DCs) and B cells respond to WNV and how rapid IgM and IgG anti-WNV neutralizing Abs develop. We hypothesize that initial innate programming of DC subsets dictate both the quality and the duration of protective Ab responses to WNV. To investigate this hypothesis we will conduct the following Specific Aims: Aim 1: We will compare the course of pathogenic WNV Texas (WN-TX) and attenuated WNV Madagascar (WN-MAD) strains early after in vivo infection. We propose that high and low pathogenic WNVs differ in how they infect, alter and program DCs. We will quantify changes early after infection in DC subset numbers, survival, cytokine production and infection. With Project 1, we will determine what innate immune factors regulate initial DC responses and susceptibility to WNV infection by comparing DC responses and infection in wildtype (WT) mice vs. C3 and IPS-1 KO mice Using mixed bone marrow (BM) chimeras, in which DCs have been ablated, we will determine how DC ablation or the absence in DCs of IPS-1, TLR-3 or other innate immune factors affects early events after WNV infection. Aim 2: To determine the molecular and cellular requirements for the development of rapid IgM neutralizing antibody responses to WNV. To determine the role of marginal zone (MZ) B cells in protective IgM immunity to WNV, we will assess IgM responses and susceptibility of MZ B cell-deficient CD22 KO and Notch2fl/fl conditional KO mice. DCs play a pivotal role in rapid IgM responses to encapsulated bacteria; using mixed BM chimeras, in which DCs have been ablated, we will determine how DC ablation or the absence in DCs of IPS-1, BAFF or other innate immune factors affects the development of neutralizing IgM Ab responses. Aim 3: We will investigate if MZ B cells are required for immune IgM to promote protective IgG immunity. Delivery of Ag to MZ-associated DCs can lead to a strong IgG antibody response. We will examine if delivery of WNV E protein to MZ DCs can induce IgM and IgG neutralizing Ab responses, and if so whether this form of Ag delivery can be used to induce protective, sterilizing immunity to WNV. These studies will lead to new insights into how best to design vaccines to WNV and other flaviviruses.