Host Genetic Susceptibility and Immune Responses to Norovirus Infections

描述(申请人提供)：诺如病毒(NOV)是全球食源性疾病和急性非细菌性胃肠炎的最常见原因。缺乏细胞培养和动物模型阻碍了在理解宿主易感性和宿主-病毒相互作用方面的进展。近年来，新城疫病毒已被确定为引起旅行者腹泻的重要肠道病原体。首席研究员有一个独特的机会，在一大群(n=600)前往墨西哥、印度或秘鲁的美国游客中研究宿主遗传决定因素和对NOV胃肠炎的免疫反应。我们的长期目标是：1)确定NOV感染易感性的重要遗传决定因素和宿主免疫机制，以进一步开发针对NOV的疫苗；2)识别可能从疫苗接种中受益最大的脆弱人群。为了实现这些目标，我们提出了以下具体目标：1)评估分泌器状态是否是新城疫感染风险、临床感染严重程度和粪便病毒脱落水平的重要决定因素；2)研究先前存在的新城疫抗体在预防新城疫感染中的作用；3)评估新城疫腹泻患者所诱发的细胞免疫反应。第一个具体目标将通过唾液样本的分泌物表型分析和血清样本的基因分型来实现。NOV的检测将通过实时定量聚合酶链式反应和血清抗体转换进行。第二个目标将通过评估先前存在的抗NOV抗体和评估被检测抗体的潜在中和能力，以及体外抑制VLP与组织血型抗原碳水化合物的结合来实现。第三个目标将通过测量粪便样本和NOV病毒样颗粒刺激外周血单核细胞的细胞因子来实现。我们将研究新城疫病毒感染时肠道免疫反应和全身免疫反应之间的相关性。该项目还将为PI发展成为一名成功的肠道疾病独立临床调查员提供必要的培训和技能。相关性(见说明)：新冠病毒是食源性疾病的重要肠道病原体，每年在美国感染约2300万人。易感人群包括餐馆顾客、儿童、老年人、住院病人、军人和旅行者。NOV具有低感染剂量、易传播、环境稳定性和对清洁剂的抵抗力等特点，被认为是生物恐怖主义的B类候选毒剂。

DESCRIPTION (provided by applicant): Noroviruses (NoVs) are the most common cause of foodborne illnesses and acute non-bacterial gastroenteritis worldwide. The lack of a cell culture and animal model has hindered progress in understanding host susceptibility and host-viral interactions. Recently, NoVs have been identified as an important enteric pathogen of travelers' diarrhea. The principal investigator has a unique opportunity to study host genetic determinants and immune responses to NoV gastroenteritis in a large (n = 600) prospective cohort of US travelers to Mexico, India, or Peru. Our longterm goals are to: 1) to define important genetic determinants of susceptibility and mechanisms of host immunity to NoV infection to further vaccine development against NoVs, and 2) to identify vulnerable populations who may most benefit from vaccination. In order to achieve these goals, we propose the following specific aims: 1) to evaluate whether secretor status is an important determinant of risk of NoV infection, clinical severity of infection, and level of fecal viral shedding; 2) to study the role of preexisting antibodies to NoVs in protection against NoV infection; 3) to evaluate the cellular immune response elicited in subjects with NoV diarrhea. The 1st specific aim will be accomplished by secretor phenotyping with saliva specimens and genotyping from serum samples. NoV detection will be performed with quantitative real-time PCR and serum antibody conversion. The 2nd aim will be achieved by evaluating for preexisting anti-NoV antibodies and assessing for potential neutralization capacity of detected antibodies, with in vitro inhibition of VLP binding to histo-blood group antigen carbohydrates assays. The 3rd aim will be accomplished by measuring cytokines from fecal specimens and from NoV virus-like particle stimulation of peripheral blood mononuclear cells. The correlation between the intestinal immune response and the systemic immune response to NoV infection will be studied. This project will also provide essential training and skills for the development of the PI into a successful independent clinical investigator of enteric diseases. RELEVANCE (See instructions): NoVs are important enteric pathogens of foodborne diseases and infects approximately 23 million people annually in the US. Susceptible populations include restaurant patrons, children, elderly, institutionalized patients, the military, and travelers. With a low infectious dose, ease of transmission, environmental stability, and resistance to cleansing agents, NoVs are considered as a Category B candidate agent of bioterrorism.