Can persistent gamma-herpesviruses be purged from the host?

描述（由申请方提供）：人γ-疱疹病毒、EB病毒（EBV）和卡波西肉瘤相关疱疹病毒（KSHV）可引起与多种恶性肿瘤发生相关的持续性感染。尽管感染的裂解期由免疫系统控制，但病毒通过建立终身潜伏期来逃避免疫，即使在免疫活性宿主中也是如此。感染的病理后果主要与病毒潜伏期相关，并且没有预防性或治疗性疫苗可用。B细胞是潜伏病毒的主要储存库，并且与EBV感染相关的一个重要临床问题是在移植后免疫抑制后发生B细胞淋巴增生性疾病和/或B细胞淋巴瘤。利妥昔单抗（抗B细胞抗体疗法）在移植后恶性肿瘤中靶向EBV转化的B细胞的临床应用的有希望的结果表明，抗B细胞疗法可用于预防性地显著降低潜伏负荷或甚至在移植前清除宿主的潜伏期。为了测试这种方法和其他治疗方法，必须了解维持长期潜伏期的机制，这可以在实验动物模型中得到最好的阐明。Gamma HV 68（也称为MHV-68）是一种自然发生的γ-疱疹病毒的啮齿类动物感染的实验室小鼠，提供了一个易于操作的小动物自然感染模型进行实验不可能在man. The目前的建议利用小鼠模型，以解决潜在的潜伏期的维护机制。重要的是，我们将测试的假设，潜伏的病毒可以从受感染的主机清除。在目标1中，我们将确定病毒再活化和再感染是否有助于维持B细胞、巨噬细胞和树突状细胞中的长期潜伏期。在目标2中，我们将确定用B细胞耗竭抗体模拟利妥昔单抗治疗，有或没有抗病毒药物，是否可以减少或消除长期潜伏期。公共卫生相关性：γ-疱疹病毒是致癌病毒，在人群中广泛传播，并与恶性肿瘤的发生有关。对γ-疱疹病毒感染的成熟小鼠模型的分析提供了一种重要的工具来剖析病毒潜伏期再激活中的基本事件，并用作测试概念治疗策略验证的体内模型。所产生的数据将通过增强我们对γ-疱疹病毒潜伏期的理解来推进该领域，以促进人类γ-疱疹病毒治疗策略的发展。

DESCRIPTION (provided by applicant): The human gamma-herpesviruses, Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV), establish persistent infections that are associated with the development of a variety of malignancies. Whereas the lytic phase of the infection is controlled by the immune system, the viruses evade immunity by establishing life-long latency, even in an immunocompetent host. Pathological consequences of infection are primarily associated with viral latency, and no prophylactic or therapeutic vaccines are available. B cells are the major reservoir of latent virus, and one important clinical problem associated with EBV infection is the development of B cell lymphoproliferative disease and/or B cell lymphomas following post-transplant immunosuppression. Promising results with the clinical use of Rituximab (anti-B cell antibody therapy) to target EBV-transformed B cells in post-transplant malignancies suggest the possibility that anti-B cell therapy could be used prophylactically to substantially lower latent load or even to purge latency from the host prior to transplantation. In order to test this and other therapeutic approaches, it is essential to understand mechanisms involved in maintenance of long-term latency, which can best be elucidated in an experimental animal model. Gamma HV68 (also referred to as MHV-68) is a naturally occurring gamma-herpesvirus of rodents that infects the laboratory mouse, providing an easily manipulated small animal natural infection model for performing experiments not possible in man. The current proposal exploits the mouse model to address mechanisms underlying the maintenance of latency. Importantly, we will test the hypothesis that latent virus can be purged from an infected host. In Aim 1, we will determine whether viral reactivation and re-infection contribute to the maintenance of long-term latency in B cells, macrophages and dendritic cells. In Aim 2 we will determine whether treatment with B cell depleting antibodies to mimic Rituximab therapy, with or without anti-viral drugs, can reduce or eliminate long-term latency. PUBLIC HEALTH RELEVANCE: The gamma-herpesviruses are oncogenic viruses that are widely disseminated in the human population and associated with the development of malignancies. Analysis of the well-developed mouse model of gamma- herpesvirus infection provides an important tool to dissect fundamental events in the reactivation of viral latency, and serves as an in vivo model for testing proof of concept therapeutic strategies. The data generated will advance the field by enhancing our understanding of gamma-herpesvirus latency to facilitate the development of therapeutic strategies for the human gamma-herpesviruses.