Immune Mechansims of Rotavirus Protection & Clearanace

轮状病毒是全世界幼儿严重肠胃炎的主要病因。预防轮状病毒感染的疫苗每年可在发展中国家防止50多万人死亡，并为美国每年节省10亿多美元的保健费用，但最近，由于相关的副作用，唯一获得许可的疫苗被撤回。预防轮状病毒感染和由此引起的疾病依赖于免疫反应的启动和维持。本应用程序的目的是了解和比较由活轮状病毒感染和非复制亚单位疫苗（VLPs）诱导的保护性免疫反应的差异。对活轮状病毒感染和VLP疫苗的免疫反应将由许多因素区分，包括反应时间、控制反应的细胞类型和免疫记忆的建立。在小鼠中，轮状病毒感染和接种VLP可诱导绝育免疫。轮状病毒和VLPs诱导小鼠绝育免疫的确切机制尚不清楚。我假设：(I)由原发性轮状病毒感染建立的清除和灭菌免疫主要是由于T细胞独立的B淋巴细胞激活，以及（ii） VLP疫苗接种将通过T细胞依赖的B淋巴细胞激活引起灭菌免疫。为了验证这一假设，流式细胞术将用于在清除原发性轮状病毒感染，接种VLP后，以及先前感染或接种VLP的小鼠遭受轮状病毒攻击后，鉴定、定量和功能表征活化淋巴细胞亚群。这将是第一次系统地识别和比较活感染动物和接种VLP动物之间的活化淋巴细胞亚群，并将这些反应与免受感染的保护联系起来的研究。了解轮状病毒和vlp疫苗如何激活免疫系统以诱导绝育免疫的机制将有助于更好地设计疫苗，并可能确定测试人类潜在疫苗有效性的基准。

Rotavirus is the leading cause of severe gastroenteritis in young children worldwide. A vaccine to prevent a rotavirus infection would prevent over 500,000 deaths/year in developing countries and save the United States over $1 billion a year in health care costs, but recently, the only licensed vaccine was withdrawn due to associated side effects. Protection from rotavirus infection and resulting disease is dependent on the initiation and maintenance of an immunological response. The goal of this application is to understand and compare the difference in protective immunological responses induced by a live rotavirus infection and by a non-replicating subunit vaccine (VLPs). The immunological response to both live rotavirus infection and a VLP vaccine will be differentiated by many factors including the time of response, the type of cells that control the response, and establishment of immunological memory. In mice, rotavirus infection and VLP vaccination can induce sterilizing immunity. The exact mechanisms through which rotavirus and VLPs induce sterilizing immunity in the mouse have not been elicited. I hypothesize that (i) clearance of and sterilizing immunity established by a primary rotavirus infection occurs predominately as a result of T cell independent B lymphocyte activation, and (ii) VLP vaccination will cause sterilizing immunity through T cell dependent B lymphocyte activation. To test this hypothesis, flow cytometry will be used to identify, quantitate, and functionally characterize activated lymphocyte subsets during clearance of a primary rotavirus infection, after vaccination with VLPs, and after a rotavirus challenge of previously infected or VLP vaccinated mice. These will be the first studies to systematically identify and compare subsets of activated lymphocytes between a live infected and VLP vaccinated animal and correlating these responses with protection from infection. Understanding the mechanisms of how rotavirus and vaccination with VLPs activate the immune system to induce sterilizing immunity will aid in better vaccine design and may identify benchmarks for testing potential vaccine effectiveness in humans.