HCMV infection and immune modulation in a human placentation model in SCID mice

描述(申请人提供)：原发人类巨细胞病毒(HCMV)感染影响1-3%的孕妇，在25%的先天性感染婴儿中导致宫内生长受限(IUGR)和永久性出生缺陷。有症状的婴儿通常在新生儿期死亡，大多数幸存者都有永久性的衰弱后遗症，包括智力低下、视力丧失和感觉神经性耳聋。这一应用建立在我们对发育中的胎盘中人巨细胞病毒感染模式的了解以及通过研究体外感染和先天性感染的人胎盘而获得的母体抗体的保护。由于宿主范围的极端限制，病毒如何传播到胎盘以及免疫防御如何减少HCMV复制仍未解决。建立人胎盘绒毛肾被膜下移植的严重联合免疫缺陷(SCID)小鼠模型，研究胎儿细胞滋养层细胞在体内的血管效应。在人类胎盘植入中，细胞滋养细胞分化，经历小动脉的强烈侵袭，并迁移到肾实质深处。这些细胞能诱导巨大的淋巴管生成反应，并形成类似于人类蜕膜的淋巴管。我们已经开始研究人类胎盘和蜕膜异种移植中的HCMV感染，并将其与子宫-胎盘交界处的病毒复制进行比较。初步研究表明，致病菌株VR1814感染细胞滋养层细胞，并以与先天性感染胎盘相似的模式复制。与胎盘植入物相比，病毒在感染的蜕膜植入物中广泛传播，这表明不同的组织环境影响体内的复制水平。我们的总体假设是：(I)可以在人类胎盘形成模型中研究SCID小鼠的HCMV感染，(Ii)致病株可用于确定其组织微环境中细胞中病毒嗜性的决定因素，以及(Iii)中和抗HCMV抗体可减少胎盘感染。此外，我们提出了干扰素-？调节体内的病毒复制。这一假说的证实将直接关系到预防先天性感染和疾病的临床应用。具体目标如下。目的1.在人胎盘植入模型中研究人巨细胞病毒在SCID小鼠胎盘和蜕膜中的复制和病毒传播。目的2.在病毒中和抗体和干扰素存在的情况下，评价人胎盘和蜕膜组织中人巨细胞病毒的复制。表情。对于临床应用来说，尤其重要的是确定人类胎盘植入物用于评估HCMV发病机制的效用，以及为减少子宫和胎盘微环境中的感染而量身定做的新型抗病毒策略。 公共卫生相关性：在严重联合免疫缺陷(SCID)小鼠模型中，人类胎盘和蜕膜植入物中HCMV感染的研究信息将直接导致新的临床干预措施的实际应用，这些干预措施可以减少子宫-胎盘界面的病毒复制，评估在诊断测试中潜在使用的病毒蛋白，识别能够诱导有效的中和抗体的病毒糖蛋白，并开发新的策略来增强胎盘的固有免疫防御。

DESCRIPTION (provided by applicant): Primary human cytomegalovirus (HCMV) infection affects 1-3% of pregnancies, causing intrauterine growth restriction (IUGR) and permanent birth defects in 25% of congenitally infected babies. Symptomatic infants often succumb in the neonatal period, and most survivors have permanent debilitating sequelae, including mental retardation, vision loss and sensorineural deafness. This application builds on our knowledge of patterns of HCMV infection in the developing placenta and protection by maternal antibodies gained by studying the human placenta infected in vitro and congenitally infected in utero. How virus disseminates to the placenta and how immune defenses reduce HCMV replication are still unresolved due to the extreme host range restriction. A new severe-combined immunodeficient (SCID) murine model of human placental villi transplanted beneath the kidney capsule was established to study the vascular effects of fetal cytotrophoblasts in vivo. In human placental implants, cytotrophoblasts differentiate, undergo robust invasion of arterioles and migrate deep into the kidney parenchyma. The cells induce a dramatic lymphangiogenic response and formation of lymphatic vessels comparable to the human decidua. We have begun to study HCMV infection in human placental and decidual xenografts, also recently developed, and compare these with viral replication at the uterine-placental interface. Preliminary studies showed that the pathogenic strain VR1814 infected cytotrophoblasts and replicated in patterns that were comparable to those seen in congenitally infected placentas. In contrast to placental implants, virus spread extensively in infected decidual implants suggesting that different tissue environments affect levels of replication in vivo. Our overarching hypothesis is that (i) HCMV infection can be studied in a model of human placentation in SCID mice, (ii) pathogenic strains can be used to define determinants for viral tropism in cells within their tissue microenvironment, and (iii) neutralizing anti-HCMV antibodies reduce infection in the placenta. Further, we propose that IFN-? modulates viral replication in vivo. Confirmation of this hypothesis will be directly relevant to clinical applications for the prevention of congenital infection and disease. The specific aims are as follows. Aim 1. Study HCMV replication and virus dissemination in placental and decidual implants in a model of human placentation in SCID mice. Aim 2. Evaluate HCMV replication in human placental and decidual implants in the presence of virus neutralizing antibodies and IFN-? expression. Especially important for clinical applications will be firmly establishing the utility of human placental implants to evaluate HCMV pathogenesis and novel antiviral strategies tailored to reduce infection in the uterine and placental microenvironments. PUBLIC HEALTH RELEVANCE: Information from studies of HCMV infection in human placental and decidual implants in the severe combined immunodeficiency (SCID) mouse model will lead directly to practical application of new clinical interventions that reduce viral replication at the uterine-placental interface, assess viral proteins with potential use in diagnostic tests, identify viral glycoproteins that elicit potent neutralizing antibodies, and develop novel strategies to bolster innate immune defenses in the placenta.