Anti-viral DC/NK interactions

描述（由申请人提供）：人类在其次级淋巴器官中含有大量的自然杀伤细胞（NK）。这些NK细胞富含免疫调节性CD56brightCD16-细胞，它们优先被树突状细胞（dc）激活。我们的初步数据表明，dc对NK细胞的激活限制了eb病毒（EBV）在体外对B细胞的转化，特别是当NK细胞来自扁桃体（EBV原发性感染的继发淋巴器官）时。EBV是一种人类肿瘤病毒，在90%以上的成年人群中存在潜伏感染。它在免疫正常的个体中引起上皮细胞和B细胞起源的肿瘤，在免疫受损的个体中发生率增加。对EBV的先天免疫的表征是特别有趣的，因为这种初始免疫控制的失败可能导致病毒滴度增加和在初级免疫反应期间大量T细胞扩增，导致感染性单核细胞增多症。为了描述DC/NK细胞相互作用在EBV感染中的作用，我们计划：1。描述EBV感染期间先天NK细胞活化的特征。我们将解剖DC/NK细胞突触的形成，EBV衍生的dsRNA对DC的激活，以及扁桃体DC亚群对EBV的激活。2. 分析扁桃体NK细胞的保护效应功能。我们将重点研究细胞因子的产生、细胞毒性以及NK细胞通过EBV感染激活DC后对保护性T细胞极化的帮助。3. 研究EBV在体内的感染。为了将我们的体外研究结果转化为EBV原发性感染的体内模型，我们在免疫受损小鼠中重建了人类免疫系统，使其能够对EBV产生初级保护性免疫反应。该模型将探讨NK细胞在EBV原发感染过程中的扩增和活化，NK细胞对EBV先天免疫控制的贡献，以及它们在EBV适应性免疫控制的T细胞极化中的辅助作用。这些研究将在体外和体内研究dc活化NK细胞的机制，以及NK细胞对eb病毒致瘤性B细胞转化的保护功能。建立EBV保护性特异性免疫控制的知识可能提示针对常见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：eb病毒（EBV）在人群中引起上皮细胞和B细胞来源的肿瘤，如霍奇金淋巴瘤和鼻咽癌。本研究计划研究先天免疫系统的两种细胞类型，树突状细胞和自然杀伤细胞如何相互作用，初步控制EBV并影响其他免疫细胞，从而建立终身保护，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，对这些初始事件的理解将有助于我们解释为什么有些人会出现EBV的症状性急性感染，称为感染性单核细胞增多症，并确定应该利用的免疫区室来有效地接种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.