Fenaux M, Cuadras M A, Feng N, Jaimes M, Greenberg H B
Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305, USA.
J Virol. 2006 Jun;80(11):5219-32. doi: 10.1128/JVI.02664-05.
Although rotavirus infection has generally been felt to be restricted to the gastrointestinal tract, over the last two decades there have been sporadic reports of children with acute or fatal cases of rotavirus gastroenteritis testing positive for rotavirus antigen and/or nucleic acid in various extraintestinal locations such as serum, liver, kidney, bladder, testes, nasal secretions, cerebrospinal fluid, and the central nervous system. Recently, studies in animals and people have demonstrated that rotavirus antigenemia is a common event during natural infection. In this study, we extend these observations and compare the intestinal and extraintestinal spread of wild-type homologous murine rotavirus EC and a heterologous strain, rhesus rotavirus (RRV), in newborn mice. A strand-specific quantitative reverse transcription-PCR (ssQRT-PCR) assay was used to quantify the ability of different rotavirus strains to spread and replicate extraintestinally. Both strain EC and RRV were detected extraintestinally in the mesenteric lymph nodes (MLN), livers, lungs, blood, and kidneys. Extraintestinal replication, as measured by ssQRT-PCR, was most prominent in the MLN and occurred to a lesser degree in the livers, kidneys, and lungs. In the MLN, strain EC and RRV had similar (P < 0.05) RNA copy numbers, although EC was present at a 10,000-fold excess over RRV in the small intestine. Rotavirus nonstructural protein 4 (NSP4) and/or assembled triple-layered particles, indicated by immunostaining with the VP7 conformation-dependent monoclonal antibody 159, were detected in the MLN, lungs, and livers of EC- and RRV-inoculated mice, confirming the ssQRT-PCR findings. Infectious RRV was detected in the MLN in quantities exceeding the amount present in the small intestines or blood. The cells in the MLN that supported rotavirus replication included dendritic cells and potentially B cells and macrophages. These data indicate that extraintestinal spread and replication occurs commonly during homologous and some heterologous rotaviral infections; that the substantial host range restrictions for rhesus rotavirus, a heterologous strain present in the intestine, are not necessarily apparent at systemic sites; that the level and location of extraintestinal replication varies between strains; that replication can occur in several leukocytes subsets; and that extraintestinal replication is likely a part of the normal pathogenic sequence of homologous rotavirus infection.
尽管人们普遍认为轮状病毒感染局限于胃肠道，但在过去二十年中，有零星报道称患有急性或致命性轮状病毒胃肠炎的儿童在血清、肝脏、肾脏、膀胱、睾丸、鼻分泌物、脑脊液和中枢神经系统等各种肠外部位的轮状病毒抗原和/或核酸检测呈阳性。最近，对动物和人的研究表明，轮状病毒血症在自然感染期间是常见现象。在本研究中，我们扩展了这些观察结果，并比较了野生型同源鼠轮状病毒EC和异源株恒河猴轮状病毒（RRV）在新生小鼠中的肠道和肠外传播情况。使用链特异性定量逆转录PCR（ssQRT-PCR）测定法来量化不同轮状病毒株在肠外传播和复制的能力。在肠系膜淋巴结（MLN）、肝脏、肺、血液和肾脏中均检测到了EC株和RRV株。通过ssQRT-PCR测定，肠外复制在MLN中最为显著，在肝脏、肾脏和肺中的程度较低。在MLN中，EC株和RRV株的RNA拷贝数相似（P<0.05），尽管在小肠中EC株的数量比RRV株多10000倍。在用VP7构象依赖性单克隆抗体159进行免疫染色时，在接种EC株和RRV株的小鼠的MLN、肺和肝脏中检测到了轮状病毒非结构蛋白4（NSP4）和/或组装的三层颗粒，证实了ssQRT-PCR的结果。在MLN中检测到的传染性RRV数量超过了小肠或血液中的数量。支持轮状病毒复制的MLN中的细胞包括树突状细胞以及可能的B细胞和巨噬细胞。这些数据表明，在同源和一些异源轮状病毒感染期间，肠外传播和复制普遍发生；肠道中存在的异源株恒河猴轮状病毒对宿主范围的显著限制在全身部位不一定明显；肠外复制的水平和位置因毒株而异；复制可发生在几个白细胞亚群中；并且肠外复制可能是同源轮状病毒感染正常致病序列的一部分。
