Defining immunological mechanisms of serovar cross-reactivity to develop broad spectrum protective vaccines for typhoidal and non-typhoidal Salmonella infections in humans

摘要(CETRRp5，Sztein，PL) 沙门氏菌感染。由于摄入了受污染的食物和水，包括伤寒 (主要由伤寒沙门氏菌(ST)和副伤寒沙门氏菌A(PA)引起)，以及非伤寒(NTS)和侵袭性NTS 非传染性鼻炎(INTS)感染是世界许多地区的主要公共卫生问题，包括在美国 每年导致120万人患病。多药耐药(MDR)迅速增加，缺乏 针对PA、NTS或INT的疫苗为疫苗的开发增加了新的紧迫感 对抗这些病原体，最好是广谱疫苗。发展中的主要障碍之一 沙门氏菌疫苗。准确的免疫学相关保护(COP)是针对 感染野生型(Wt)生物或疫苗仍不清楚，部分原因是ST和PA 人类限制的感染。使用来自接种和/或挑战wt ST的志愿者的样本 已经开始揭示免疫T细胞介导的免疫(T-CMI)效应机制，这可能是 与挑战后的临床结果相关。自第一个wt PA以来，没有类似的数据可用 刚刚进行了挑战。在我们对这些机制的理解上也存在着严重的差距。 不同沙门氏菌的抗原提呈，这可能是发展有效的适应性T- CMI和B细胞反应，以及在下列肠道微环境中引发的免疫反应 暴露于伤寒和新城疫感染。 出于这些原因，这项应用的总体目标是推动疫苗的开发 PA以及针对肠道发热、INT和NTS的广谱疫苗，通过识别保护性交叉 反应性沙门氏菌。体液、T效应和调节性免疫反应，无论是系统性的还是在 肠道微环境，并通过确定针对ST、PA、INTS和NTS的抗原提呈机制 这会影响适应性免疫细胞编程。为了实现这些目标，我们将使用来自(I)挑战的PBMC 使用wt PA进行的已知临床结果的研究(例如，非疾病或疾病)，(Ii)使用减弱的PA进行的研究 疫苗候选菌株CVD1902随后用wt PA攻击，(Iii)体外T细胞免疫系统和 (4)三种人体肠道模型：(A)生物工程3-D有机体，(B)肠样体，和(C)外植体 以下目标：目标1.评估循环中一组确定的B和T细胞反应是否 与预防菌血症感染和/或菌血症阴性的临床疾病(例如发烧)有关 在人类中口服wt PA后，哪些调节机制参与了 这些回应。目的2.评价ST、PA、INTS和NTS与树突状细胞之间的相互作用 (DC)导致不同途径的激活，而这些途径又决定了确定的T细胞反应的启动。 目的3.比较不同剂量不同药物对肠道天然免疫细胞分子标志物的影响及功能 沙门氏菌血清型和相应的同基因疫苗株。

ABSTRACT (CETR RP5, Sztein, PL) Infection with Salmonella spp. due to ingestion of contaminated food and water, including typhoidal (caused largely by S. Typhi (ST) and S. Paratyphi A (PA)), as well as non-typhoidal (NTS) and invasive NTS (iNTS) infections are major public health concerns in many areas of the World, including in the U.S. where NTS causes 1.2 million illnesses annually. The rapid increase in multidrug resistance (MDR) and the lack of vaccines against PA, NTS or iNTS have added a new sense of urgency for the development of vaccines against these pathogens, and ideally broad-spectrum vaccines. One of the major obstacles in developing vaccines against Salmonella spp. is that the precise immunological correlates of protection (CoP) against either infection with wild-type (wt) organisms or vaccines remain unknown, in part because ST and PA are human-restricted infections. The use of specimens from volunteers vaccinated and/or challenged with wt ST has begun to uncover immunological T cell-mediated immunity (T-CMI) effector mechanisms which might be associated with clinical outcome following challenge. No similar data is available for PA since the first wt PA challenge has just been performed. A critical gap also remains in our understanding of the mechanisms of antigen presentation for different Salmonella spp., which may underlie the development of effective adaptive T- CMI and B cell responses, as well as the immune responses elicited in the gut microenvironment following exposure to typhoidal and NTS infections. For these reasons, the overall goal of this application is to advance the development of vaccines against PA as well as broad-spectrum vaccines against enteric fevers, iNTS, and NTS, by identifying protective cross- reactive Salmonella spp. humoral, T effector, and regulatory immune responses, both systemically and in the gut microenvironment, and by defining the mechanisms of antigen presentation against ST, PA, iNTS and NTS that impact adaptive immune cell programming. To achieve these goals we will use PBMC from (i) a challenge study with wt PA with known clinical outcomes (e.g., non-disease or disease), (ii) a study with attenuated PA vaccine candidate strain CVD 1902 followed by challenge with wt PA, (iii) in vitro T cell priming systems and (iv) three human intestinal models: (a) bioengineered 3-D organoids, (b) enteroids, and (c) explants to perform the following Aims: Aim 1. Evaluate whether a defined set of B and T cellular responses in circulation are associated with protection from bacteremic infection and/or bacteremia-negative clinical disease (e.g., fever) following an oral challenge with wt PA in humans, and which regulatory mechanisms are involved in generating these responses. Aim 2. Evaluate whether interactions between ST, PA, iNTS and NTS and dendritic cells (DC) lead to the activation of diverse pathways which in turn determine the priming of defined T cell responses. Aim 3. Contrast molecular biomarker changes and function elicited in gut innate immune cells by various Salmonella serovars and the corresponding isogenic vaccine strains.