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

摘要（CETR RP 5，Sztein，PL） 沙门氏菌感染由于摄入受污染的食物和水，包括伤寒 （主要由S。伤寒（ST）和沙门氏菌（S.甲型副伤寒（PA）），以及非伤寒（NTS）和侵袭性NTS 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）的迅速增加和缺乏耐药基因的治疗， 针对PA、NTS或iNTS的疫苗为疫苗的开发增加了新的紧迫感 对抗这些病原体，理想的是广谱疫苗。发展中的主要障碍之一 针对沙门氏菌属的疫苗是保护（CoP）的精确免疫相关性， 野生型（wt）生物或疫苗的感染仍然未知，部分原因是ST和PA是 人类局限性感染使用来自接种疫苗和/或用wt ST攻毒的志愿者的标本 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 与攻毒后临床结局相关。自第一个wt PA以来，没有类似的数据可用于PA 刚刚进行了挑战。在我们对癌症机制的理解方面， 不同沙门氏菌属的抗原呈递，这可能是发展有效的适应性T- CMI和B细胞反应，以及在肠道微环境中引起的免疫反应， 暴露于伤寒和NTS感染。 由于这些原因，本申请的总体目标是推进针对以下疾病的疫苗的开发： PA以及针对肠热病、iNTS和NTS的广谱疫苗，通过鉴定保护性交叉免疫， 反应性沙门氏菌体液、T效应细胞和调节性免疫应答，包括全身性和全身性免疫应答。 肠道微环境，并通过定义针对ST、PA、iNTS和NTS的抗原呈递机制， 影响适应性免疫细胞编程的基因。为了实现这些目标，我们将使用来自（i）激发的PBMC 具有已知临床结果的wt PA研究（例如，非疾病或疾病），（ii）使用减毒PA的研究 疫苗候选菌株CVD 1902，随后用wt PA攻击，（iii）体外T细胞引发系统，和 (iv)三种人类肠道模型：（a）生物工程3-D类器官，（B）类肠，和（c）外植体，以执行 目标：目标1。评价循环中一组确定的B和T细胞应答是否 与防止菌血症感染和/或菌血症阴性临床疾病（例如，发烧） 在人类中用wt PA进行口服攻击后，以及哪些调节机制参与产生 这些回应。目标二。评估ST、PA、iNTS和NTS与树突状细胞之间是否存在相互作用 (DC)导致不同途径的激活，这反过来又决定了确定的T细胞应答的引发。 目标3：对比各种免疫抑制剂在肠道先天免疫细胞中引起的分子生物标志物变化和功能 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.