The developing intestinal immune system in Yersinia enterocolitica infection

小肠结肠炎耶尔森菌感染中肠道免疫系统的发育

• 批准号: 7701381
• 负责人: REBECCA D ADKINS
• 金额: $ 22.95万
• 依托单位: UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-04 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7701381
• 关键词: Ablation; Acute; Address; Adjuvant; Adoptive Transfer; Adult; Antibodies; Antibody Formation; B-Lymphocytes; Bacteremia; Bacteria; Biological Models; Body Weight decreased; CD4 Positive T Lymphocytes; Cells; Cellular Structures; Child; Childhood; Colitis; Crohn' s disease; Development; Disease; Down-Regulation; Employee Strikes; Engineering; Enterobacteriaceae; Exposure to; Food; Genetic screening method; Goals; Growth; Health; Immune; Immune Targeting; Immune response; Immune system; Immunity; Immunization; Immunology; Inbred BALB C Mice; Infant; Infection; Infectious Agent; Infiltration; Inflammation; Inflammation Mediators; Inflammatory; Inflammatory Response; Inflammatory disease of the intestine; Interferons; Interleukin-17; Intestinal Mucosa; Intestines; Lead; Learning; Life; Living Wills; Microbe; Microbiology; Modeling; Molecular; Monitor; Mus; Neonatal; Newborn Infant; Oral; Ovalbumin; Ovum; Pathogenesis; Pathway interactions; Phagocytes; Proteins; Rattus; Regulation; Relative (related person); Resistance; Role; Route; Salmonella; Site; Surface; System; T-Lymphocyte; Testing; Time; Transgenic Organisms; Vaccine Antigen; Vaccines; Virulence; Virulence Factors; Yersinia; Yersinia enterocolitica; antimicrobial; cell type; cytokine; extracellular; in vivo; insight; microbial; microorganism antigen; mortality; mucosal vaccine; mutant; neonate; neutrophil; novel; novel strategies; novel therapeutics; pathogen; response; tool

DESCRIPTION (provided by applicant): The vast majority of infectious agents are encountered at mucosal surfaces. Understanding the dynamic interface of immune cells and infectious microbes at these sites is one of the greatest challenges in the fields of microbiology and immunology. These interactions are especially important in neonatal life when microbial antigens are encountered for the first time. To study immune cell/bacterial interactions during the neonatal period, we have developed a novel murine model of orogastric infection with the extracellular bacterium Yersinia enterocolitica. Strikingly, neonates are markedly more resistant than adults to this enteropathogen, an observation unique among all other studied neonate-pathogen interactions. This system provides an unprecedented opportunity for learning how fully protective immunity is achieved in the neonatal intestine. Thus, a major goal of this application is to identify the eukaryotic immune mechanisms leading to resistance of neonates to intestinal exposure to Y. enterocolitica. A second major goal of this application is to apply Y. enterocolitica products to the regulation of neonatal intestinal immunity in health and disease. These defined goals will provide major new building blocks for our long term goals of (a) understanding how intestinal immunity develops during ontogeny, (b) achieving highly effective pediatric mucosal vaccines, and (c) developing novel strategies for the treatment of pathological intestinal inflammation in early life. Specific Aim 1 will define adaptive immune mechanisms underlying protection of neonates from oral Y. enterocolitica infection. The effects of neutralization of ?IFN and/or IL-17 responses on inflammatory cell infiltration, bacteremia, and relative weight loss associated with mortality will be examined. The importance of B cell responses will be tested by genetic and acute B cell ablation and in B cell-sufficient neonates unable to mount bacterial-specific antibody responses. Lastly, the contribution of natural Treg (CD4+CD25+) will be analyzed by adoptive transfer of adult Treg to infected neonates and by the in vivo depletion of the Treg compartment. Specific Aim 2 will exploit the Y. enterocolitica effector protein YopP (its presence or its absence) to manipulate neonatal immune responses and identify key target immune cell types in vivo. Since the ?YopP mutant strain induces profound inflammation in the neonatal intestine, we will test the capacity of a modified ?YopP mutant strain to act as a potent adjuvant for mucosal immunization. An ovalbumin - expressing ?YopP strain will be created and ovalbumin-specific antibody and Th responses will be monitored, as well as the in vivo activation of ova-specific TCR transgenic T cells. Second, the possibility that YopP, by itself, can downregulate pathogenic intestinal inflammation in neonates will be tested. Bacteria (Y. enterocolitica and Salmonella) engineered to express only YopP will be applied to modulate inflammation in DSS-induced colitis in neonates. In addition, cell types critical for Y. enterocolitica pathogenesis will be identified by assessing NF?B activation in intestinal cells following infection with the ?YopP strain. Children are highly susceptible to microbes transmitted through contaminated food. This application has two main objectives. First, we will discover how the intestinal immune system in early life develops protective responses against microbes; second, we will learn how products of the microbes themselves can be used to enhance childhood vaccine responses and treat intestinal inflammation, such as pediatric Crohn's disease.

描述（由申请人提供）：绝大多数感染原是在粘膜表面遇到的。了解这些位点的免疫细胞和传染性微生物的动态界面是微生物学和免疫学领域的最大挑战之一。当新生儿第一次遇到微生物抗原时，这些相互作用尤其重要。为了研究新生儿期免疫细胞/细菌的相互作用，我们开发了一种新型的小鼠口胃感染细胞外细菌小肠结肠炎耶尔森氏菌的模型。引人注目的是，新生儿对这种肠道病原体的抵抗力明显比成人强，这一观察结果在所有其他研究的新生儿与病原体相互作用中是独一无二的。该系统为了解如何在新生儿肠道中实现充分的保护性免疫提供了前所未有的机会。因此，本申请的主要目标是确定导致新生儿对肠道暴露于小肠结肠炎耶尔森氏菌产生抵抗力的真核免疫机制。该应用的第二个主要目标是将小肠结肠炎耶尔森氏菌产品应用于健康和疾病中新生儿肠道免疫的调节。这些明确的目标将为我们的长期目标提供重要的新基石：(a) 了解个体发育过程中肠道免疫如何发展，(b) 实现高效的儿科粘膜疫苗，以及 (c) 制定治疗病理性肠道炎症的新策略在生命的早期。具体目标 1 将定义保护新生儿免受口腔小肠结肠炎耶尔森氏菌感染的适应性免疫机制。将检查中和αIFN和/或IL-17反应对炎症细胞浸润、菌血症和与死亡率相关的相对体重减轻的影响。 B 细胞反应的重要性将通过遗传和急性 B 细胞消融以及 B 细胞充足的新生儿无法产生细菌特异性抗体反应来测试。最后，将通过将成年 Treg 过继转移至受感染的新生儿以及 Treg 隔室的体内耗竭来分析天然 Treg (CD4+CD25+) 的贡献。具体目标 2 将利用小肠结肠炎耶尔森氏菌效应蛋白 YopP（其存在或不存在）来操纵新生儿免疫反应并识别体内关键目标免疫细胞类型。由于 ?YopP 突变株在新生儿肠道中诱导严重炎症，我们将测试改良的 ?YopP 突变株作为粘膜免疫的有效佐剂的能力。将创建表达卵清蛋白的?YopP菌株，并监测卵清蛋白特异性抗体和Th反应，以及ova特异性TCR转基因T细胞的体内激活。其次，将测试 YopP 本身下调新生儿致病性肠道炎症的可能性。仅表达 YopP 的细菌（小肠结肠炎耶尔森氏菌和沙门氏菌）将用于调节 DSS 诱导的新生儿结肠炎的炎症。此外，通过评估 ?YopP 菌株感染后肠道细胞中 NFκB 的激活，可以鉴定对小肠结肠炎耶尔森氏菌发病机制至关重要的细胞类型。儿童非常容易受到通过受污染食物传播的微生物的影响。该应用程序有两个主要目标。首先，我们将发现生命早期的肠道免疫系统如何对微生物产生保护性反应；其次，我们将了解如何利用微生物本身的产物来增强儿童疫苗反应并治疗肠道炎症，例如小儿克罗恩病。