Anti-viral DC/NK interactions

描述(申请人提供)：人类的次级淋巴器官中含有大量的自然杀伤(NK)细胞。这些NK细胞富含免疫调节性CD56brightCD16-细胞，树突状细胞(DC)优先激活CD56brightCD16-细胞。我们的初步数据表明，DC激活的NK细胞在体外限制了EB病毒(EBV)对B细胞的转化，特别是当NK细胞来自扁桃体时，扁桃体是EBV感染的次级淋巴器官。EBV是一种人类肿瘤病毒，它在90%以上的人类成年人口中建立了潜伏感染。它在免疫功能正常的人中引起上皮性和B细胞性肿瘤，在免疫受损的人中发病率增加。EBV先天免疫的特性尤其令人感兴趣，因为这种初始免疫控制的失败可能会导致病毒滴度的增加和初级免疫反应中T细胞的大量扩张，从而导致传染性单核细胞增多症。为了研究DC/NK细胞相互作用在EBV感染中的作用，我们计划：1.研究EBV感染过程中天然NK细胞的激活情况。我们将解剖DC/NK细胞突触的形成，EBV来源的dsRNA对DC的激活，以及扁桃体DC亚群的EBV激活。2.分析扁桃体NK细胞的保护效应功能。我们将集中于细胞因子的产生、细胞毒性以及通过EBV感染激活DC后NK细胞在保护T细胞极化中的辅助作用。3.研究EBV体内感染情况。为了将我们的体外发现转化为原发EBV感染的体内模型，我们在免疫低下的小鼠中重建了人类免疫系统，可以对EBV产生初级保护性免疫反应。该模型将用于研究初发EBV感染过程中NK细胞的扩增和激活，NK细胞在EBV天然免疫调控中的作用，以及它们在EBV获得性免疫调控中对T细胞极化的帮助。这些研究将在体外和体内研究DC激活NK细胞的机制，以及通过致癌EBV保护NK细胞抵抗B细胞转化的功能。建立保护性EBV特异性免疫控制的知识可能会建议针对常见的EBV相关肿瘤，如鼻咽癌和霍奇金淋巴瘤的疫苗接种策略。公共卫生相关性：爱泼斯坦-巴尔病毒(EBV)在人类人群中引起上皮性和B细胞性肿瘤，如霍奇金淋巴瘤和鼻咽癌。这项提议计划研究两种类型的先天性免疫系统--树突状细胞和自然杀伤细胞--如何相互作用，最初控制EBV并影响其他免疫细胞，以建立终身保护，防止EBV相关恶性肿瘤的发展。在建立EBV特异性免疫控制过程中对这些初始事件的了解将有助于我们解释为什么一些人会出现有症状的EBV急性感染，称为传染性单核细胞增多症，并确定应该利用哪些免疫间隔来有效地接种EBV相关肿瘤的疫苗。

DESCRIPTION (provided by applicant): Humans harbor a substantial Natural Killer (NK) cell compartment in their secondary lymphoid organs. These NK cells are enriched for immunoregulatory CD56brightCD16- cells, which are preferentially activated by dendritic cells (DCs). Our preliminary data demonstrate that NK cell activation by DCs restricts B cell transformation by the Epstein Barr virus (EBV) in vitro, especially when the NK cells are derived from tonsils, the secondary lymphoid organ of primary EBV infection. EBV is a human tumorvirus, which establishes latent infection in more than 90% of the human adult population. It causes tumors of epithelial and B cell origin in immune competent, and at increased frequencies in immune compromised individuals. The characterization of innate immunity to EBV is of particular interest, because failure of this initial immune control might result in increased viral titers and massive T cell expansion during primary immune responses, resulting in infectious mononucleosis. In order to characterize the role of DC/NK cell interactions during EBV infections, we plan to: 1. Characterize innate NK cell activation during EBV infection. We will dissect DC/NK cell synapse formation, DC activation by EBV derived dsRNA, and tonsillar DC subsets for their activation by EBV. 2. Analyze the protective effector functions of tonsillar NK cells. We will focus on cytokine production, cytotoxicity and assistance in protective T cell polarization by NK cells after DC activation via EBV infection. 3. Investigate EBV infection in vivo. In order to translate our in vitro findings into an in vivo model of primary EBV infection, we have reconstituted human immune systems in immune compromised mice, which could mount primary protective immune responses against EBV. This model will be explored to investigate NK cell expansion and activation during primary EBV infection, the contribution of NK cells to innate immune control of EBV, and their assistance in T cell polarization of adaptive immune control of EBV. These studies will characterize the mechanisms of NK cell activation by DCs, and protective NK cell functions against B cell transformation by oncogenic EBV in vitro and in vivo. Knowledge of the establishment of protective EBV specific immune control might suggest vaccination strategies against common EBV associated tumors like nasopharyngeal carcinoma and Hodgkin's lymphoma. PUBLIC HEALTH RELEVANCE: Epstein Barr virus (EBV) causes tumors of epithelial and B cell origin in the human population, like Hodgkin's lymphoma and nasopharyngeal carcinoma. This proposal plans to investigate how two cell types of the innate immune system, dendritic cells and Natural Killer cells, interact to initially control EBV and influence other immune cells to establish life-long protection from the development of EBV associated malignancies. An understanding of these initial events during the establishment of EBV specific immune control will help us explain why some individuals develop symptomatic acute infection with EBV, called infectious mononucleosis, and identify immune compartments that should be harnessed to efficiently vaccinate against EBV associated tumors.