Analysis of HCMV Infection of Monocytes and Macrophages

描述(申请人提供)：人类巨细胞病毒(HCMV)在免疫功能低下的人(艾滋病和移植患者，以及新生儿)中会导致严重疾病。它还与人类慢性疾病中的免疫活性有关。巨细胞病毒感染的一个关键特征是病毒的血源性传播，这是疾病发病机制的核心。人巨细胞病毒病毒血症与细胞相关，但细胞类型尚未确定。单核细胞可能是介导病毒传播的候选细胞。单核细胞是血液中感染的主要细胞类型，也是感染器官中发现的主要浸润性细胞类型。问题是，单核细胞不能有效地感染HCMV；病毒复制是流产的。巨噬细胞(从单核细胞分化而来)支持病毒的高效复制，在HCMV患者的多个组织中发现感染的巨噬细胞。然而，它们不是血液传播的细胞，不能负责血源性传播。因此，目前的发现是相互矛盾的，涉及到HCMV传播的细胞类型仍然没有解决。我们提出了一种解决这一难题的方法，即单核细胞感染巨细胞病毒，促使它们特异性地从血液中迁移到周围组织，在那里它们可以分化为巨噬细胞，然后可以通过感染的单核细胞将原始病毒从血液中复制到组织中。因此，我们认为HCMV具有驱动外渗和单核细胞向巨噬细胞分化的能力，这是病毒的关键功能。我们有初步数据支持这一提议。据我们所知，这一策略在其他病毒中的先例尚未报道，这与已知的关于HCMV发病机制的情况是一致的。我们推测，巨细胞病毒可诱导单核细胞向外周组织渗出，并分化为可产生感染的巨噬细胞。其具体目的如下：1)研究病毒结合是否启动单核细胞向巨噬细胞的分化以及巨细胞病毒感染在单核细胞外渗中的作用；2)检测病毒基因在病毒分化的巨噬细胞中的表达和复制；3)确定病毒诱导单核细胞向巨噬细胞分化的分子信号机制。总体而言，这项建议调查了人巨细胞病毒传播和持续的机制。

DESCRIPTION (provided by applicant): Human cytomegalovirus (HCMV) causes severe disease in the immunocompromised (AIDS and transplant patients, and neonates). It is also associated with chronic human diseases in the immunocompetent. A critical feature of HCMV infections is the hematogenous dissemination of the virus that is central to disease pathogenesis. HCMV viremia is cell-associated, but the cell type responsible has not been conclusively identified. Monocytes are likely candidates to mediate viral dissemination. Monocytes are the primary cell type infected in the blood and are the predominant infiltrating cell type found in infected organs. The problem is that monocytes are not productively infected by HCMV; virus replication is abortive. Macrophages (differentiate from monocytes) support productive viral replication and infected macrophages are found in multiple tissues in HCMV patients. However, they are not blood-borne cells and cannot be responsible for hematogenous spread. Thus, current findings are contradictory and the cell type involved in HCMV spread remains unresolved. We propose a solution to this apparent conundrum and that is, that HCMV infection of monocytes drives their specific migration out of the blood into peripheral tissues, where they can differentiate into macrophages and can then replicate the original virus carried from the blood into the tissue by the infected monocytes. Therefore, we suggest that HCMV possesses the ability to drive extravasation and monocyte-to-macrophage differentiation and that this is a critical function of the virus. We have preliminary data to support this proposal. To our knowledge, a precedent for this strategy in other viruses has not been reported and it is consistent with what is known about HCMV pathogenesis. We hypothesize that HCMV induces extravasation of monocytes to peripheral tissues and their differentiation into productively infected macrophages. The specific aims are as follows: 1) to investigate if viral binding initiates monocyte-to-macrophage differentiation and the role of HCMV infection in monocyte extravasation; 2) to examine viral gene expression and replication in viral differentiated macrophages; and, 3) to determine the molecular signaling mechanisms associated with the viral-induced differentiation of monocytes into macrophages. Overall, this proposal investigates the mechanisms involved in HCMV spread and persistence.