MODIFYING THE LUNG TO INDUCE STERILE VACCINE-INDUCED PROTECTION AGAINST MTB INFECTION

项目摘要 结核分枝杆菌 (Mtb) 和人类免疫缺陷病毒 (HIV) 共同代表 世界上最大的杀手。据估计，每年诊断出 900 万新结核病 (TB) 病例 年，每年造成 140 万人死亡。因此，开发新颖的产品至关重要 控制 Mtb 感染的策略。目前唯一获得许可的结核病疫苗是牛分枝杆菌卡介苗 盖林 (BCG) 对儿童结核病有效，但对肺结核疗效有限 青春期后。因此，开发新的结核病疫苗和治疗方法将提供更好的治疗效果。 迫切需要针对结核分枝杆菌接触采取保护措施。正在开发的现代候选结核疫苗 专注于诱导强烈的 T 细胞反应，主要是产生细胞因子的 CD4 T 细胞 干扰素 γ（IFN-γ、Th1 细胞）。最近，粘膜白细胞介素 17A (IL-17) 在 疫苗诱导的针对结核病的保护作用也已得到证实。因此，诱导肺驻留IL- 还正在探索通过粘膜结核疫苗产生 17 CD4 T 细胞群（Th17 细胞）。 然而，大多数结核病疫苗并不赋予灭菌免疫力，相反，仅导致约 0.5 至 1.5 记录动物挑战模型中肺 Mtb 负荷。我们在此提供的新数据表明，缺乏 消除疫苗诱导的结核疫苗免疫并非由于疫苗诱导的 CD4 功能不良 T 细胞，但由于以下原因导致肺中回想起 CD4 T 细胞反应的延迟激活和积累 结核分枝杆菌感染。使用新颖的策略，我们表明可以通过提供激活的 Mtb 抗原 (Ag) 脉冲树突状细胞 (DC) 进入接种 Mtb 感染小鼠的肺部。直流传输 大大加速了 CD4 T 细胞在肺部积累的时间，并产生了更好的疫苗 在感染 Mtb 的疫苗接种小鼠中诱导免疫力。使用 RNASeq 分析，我们进一步生成了 接受 DC 移植的接种小鼠的基因特征，与优质疫苗相关 Mtb 感染后诱导的免疫力。该基因特征反映了相关途径的上调 快速有效地激活肺 DC 和 T 细胞通路。具体来说，我们发现了基因 与 DC 转移受体中 CD103 DC 激活和 CD40 通路上调相关 接种疫苗的 Mtb 感染小鼠，表现出优异的 Mtb 控制能力。在这个探索性提案中，使用鼠标 疫苗接种和 Mtb 感染模型，我们将研究是否针对宿主肺 CD103 DC CD40 通路与新型宿主定向疗法 (HDT) 可以诱导灭菌疫苗 Mtb 感染后诱导免疫。这些研究将在功能上确定其机制 介导疫苗诱导的 T 细胞对结核病的记忆反应的快速激活。重要的是，这些研究将 还提供新型 HDT 来增强疫苗反应，以控制受感染宿主的 Mtb 负担，或 延迟潜伏感染者的结核病重新激活。

PROJECT ABSTRACT Mycobacterium tuberculosis (Mtb) and human immunodeficiency virus (HIV) together represent the world's biggest killers. There are an estimated nine million new cases of tuberculosis (TB) diagnosed each year, resulting in 1.4 million deaths annually. It is therefore of paramount importance that we develop novel strategies for controlling Mtb infection. The only currently-licensed vaccine for TB, M.bovis Bacille Calmette Guerin (BCG), is effective against childhood forms of TB, but has limited efficacy against pulmonary TB after adolescence. Thus, development of novel vaccines and therapeutics for TB that will provide improved protection upon Mtb exposure are urgently required. Modern candidate TB vaccines under development have focussed on induction of strong T cell responses, primarily CD4+ T cells producing the cytokine interferon gamma (IFN-γ, Th1 cells). More recently, a key role for mucosal interleukin 17A (IL-17) in vaccine-induced protection against TB disease has also been shown. Thus, induction of lung-resident IL- 17-producing CD4+ T cell populations (Th17 cells) by mucosal TB vaccines is also being explored. However, most TB vaccines do not confer sterilizing immunity, instead, inducing a reduction of only ~0.5 to 1.5 logs in lung Mtb burden in animal challenge models. Our new data presented here, show that the lack of sterilizing vaccine-induced immunity to TB vaccines is not due to poor function of vaccine-induced CD4+ T cells, but due to delayed activation and accumulation of recall CD4+ T cell responses in the lung following Mtb infection. Using novel strategies, we show that this bottleneck can be overcome by delivery of activated Mtb antigen (Ag)-pulsed dendritic cells (DCs) into the lungs of vaccinated Mtb-infected mice. DC transfer substantially accelerates the timing of CD4+ T cell accumulation in the lungs, and leads to superior vaccine- induced immunity in Mtb-infected vaccinated mice. Using RNASeq analysis, we have further generated a gene signature in vaccinated mice receiving DC transfer, that is associated with the superior vaccine immunity induced upon Mtb infection. This gene signature reflects upregulation of pathways associated with rapid and effective activation of lung DCs and T cell pathways. Specifically, we found genes associated with activation of CD103+ DC and CD40 pathways upregulated in DC transfer-recipient vaccinated Mtb-infected mice, exhibiting superior Mtb control. In this exploratory proposal, using mouse models of vaccination and Mtb infection, we will investigate whether targeting host lung CD103+ DCs and the CD40 pathway with novel host-directed therapeutics (HDTs) can induce sterilizing vaccine- induced immunity following Mtb infection. These studies will functionally determine the mechanisms that mediate rapid activation of vaccine-induced T cell recall responses to TB. Importantly, these studies will also provide novel HDTs to enhance vaccine responses to either control Mtb burden in infected hosts, or delay TB reactivation in latently-infected individuals.