Borna病病毒及Borna病

20 0多年前 ,Ｂｏｒｎａ病 (ＢｏｒｎａｄｉｓｅａｓｅＢＤ)首先被描述为发生在德国东南部的一种马致死性神经疾病。 1885年 ,该病在德国Ｓａｘｏｎｙ州的Ｂｏｒｎａ镇周围流行而导致大批的马匹死亡 ,因而本病即以该镇命名〔1〕。研究表明 ,该病是一种以行为异常、脑实质和脑膜     

Borna病病毒感染的实验室诊断

Boma病病毒(Borna disease virus，BDV)是目前已知惟一在核内复制的非分段单分子负链RNA病毒，具有严格的嗜神经性，在感染细胞内呈低量、非溶细胞性复制。相关的最早报道德国在1885年，当时将流行于马群中的一种致死性脑炎命名为Borna病，但是直到1990年，才成功地从感染动物脑内分离到了BDV。目前可确定的是自然感染主要发生在马和羊，而动物实验发现BDV能感染几乎所有的恒温     

Genomic RNAs of Borna disease virus are elongated on internal template motifs after realignment of the 3' termini

The terminal structures of the Borna disease virus (BDV) genome (vRNA) and antigenome (cRNA) differ from those of other negative strand RNA viruses, as both molecules possess four nucleotides at the 3' terminus without an apparent template at the 5' end of the opposite strand. Consequently, the v- and cRNA molecules are not perfect mirror images, a situation that is not compatible with conventional strategies to maintain genetic information. We show here that recombinant viruses recovered from cDNA lacking the nontemplated nucleotides efficiently reconstitute the 3' overhangs. Analyses of recombinant viruses encoding genetic markers in potential alternative template sequences demonstrated that the BDV v- and cRNA molecules are extended by a realign-and-elongation process on internal template motifs located in close proximity to the 3' ends of v- and cRNA, respectively. The data further suggest that cRNA elongation is restricted to a single template motif of the nascent strand, whereas elongation of vRNA might use multiple template motifs. We propose that the elongation of the 3' termini supports the terminal integrity of the genomic RNA molecules during BDV persistence, and furthermore provides an elegant strategy to eliminate the triphosphate groups from the 5' termini of the BDV v- and cRNA without compromising the genetic information of the virus.     

Search for Borna disease virus in Danish fibromyalgia patients

OBJECTIVE: The purpose of this study was to look for Borna disease virus (BDV) in 18 patients with acute onset of fibromyalgia (FMS) following a "flu-like" episode. BDV is a neurotropic RNA virus affecting horses and sheep. Infections in animals have been reported to cause immune mediated disease characterized by abnormalities in behavior. A possible link between BDV and neuropsychiatric diseases in man has been described, and lately a connection to chronic fatigue syndrome (CFS) has been suggested. METHODS: A BDV-specific nested PCR (RT-PCR) was performed on serum and spinal fluid. RESULTS: The BDV genome was not detected in any of the FMS cases. CONCLUSION: Although BDV was not demonstrated in spinal fluid or serum from the tested patients with FMS, we believe that it is important to report our results, since FMS can exhibit many manifestations in common with CFS. Possible reasons for the discrepant findings are discussed.     

Borna disease virus, a negative-strand RNA virus, transcribes in the nucleus of infected cells.

Borna disease virus, an unclassified infectious agent, causes immune-mediated neurologic disease in a wide variety of animal hosts and may be involved in pathogenesis of selected neuropsychiatric diseases in man. Initial reports suggested that Borna disease virus is a single-stranded RNA virus. We describe here a method for isolation of viral particles that has allowed definitive identification of the genome as containing a negative-polarity RNA. Further, we show that the viral mRNAs are transcribed in the nucleus.     

Infection with Borna disease virus: molecular and immunobiological characterization of the agent.

Borna disease virus (BDV), which seems to be distinct from all other known viruses, exhibits a unique mechanism of pathogenesis. This review highlights several aspects of the biology of infection with this virus and summarizes the preliminary characterization of the agent. Studies on BDV may help to illuminate several important areas of neurobiology, including the mechanisms regulating the replication of a new type of RNA virus in the nuclei of neural cells, the neuroinvasiveness and neurotropism of such viruses, their T cell-mediated immunopathology, tolerance in newborn animals to persistent viral infection of the central nervous system, and behavioral diseases and eating disorders induced by such agents.     

博尔纳病病毒核蛋白转染人少突胶质细胞的蛋白组学研究

目的 研究博尔纳病病毒(Borna disease virus)核蛋白(Nucleoprotein,p40)质粒转染人少突胶质细胞(Oligodendrocyte,OL)后蛋白表达变化。方法 构建BDVp40质粒转染OL细胞的细胞模型和空载体转染细胞模型,分别提取各组细胞蛋白进行双向凝胶电泳和图像分析,用HPLC-Chip/MS纳流液质联用技术进行差异蛋白分析,NCBI数据库搜索鉴定差异蛋白。结果 BDVp40转染后出现蛋白表达差异,与对照组相比有8个蛋白表达上调,4个蛋白表达下调,1个蛋白只在转染后细胞表达而未转染OL细胞组不表达,其中4个蛋白与神经系统疾病相关。结论 BDVp40转染OL细胞后导致相关蛋白表达改变,其中一部分蛋白与神经系统疾病相关。     

抗博尔纳病病毒磷蛋白单克隆抗体的制备及鉴定

目的以重组的博尔纳病病毒(BDV)磷蛋白(p24)为免疫原制备单克隆抗体,并鉴定其特异性。方法以纯化后的重组BDVp24免疫小鼠,将骨髓瘤细胞与其脾细胞进行融合,经ELISA法筛选出分泌抗p24单抗的细胞株,并对其进行克隆与亚克隆培养,将最终获得的其中2株细胞株分别注入小鼠腹腔制备单抗,经亲和纯化法纯化后,采用ELISA法测定效价,利用蛋白免疫印迹和免疫荧光鉴定其特异性。结果建立了2株稳定分泌抗p24单抗的杂交瘤细胞株,抗体亚类均为IgG1型。纯化后的腹水抗p24单抗纯度为98%和93%,ELISA效价在1∶81 000以上,该抗体均能识别重组p24蛋白和BDV感染人类少突胶质细胞(Oligodendroglia cell,OL细胞)所表达的p24蛋白。结论成功制备了灵敏性高、特异性好的抗BDVp24单抗,为博尔纳病病毒诊断方法的研制及感染机理的研讨提供依据。     

牧羊犬外周血和脑组织博尔纳病病毒检测结果的比较

目的检测同一牧羊犬外周血和脑组织博尔纳病病毒(BDV)p24片段,比较两者阳性率的差异。方法采用改进的荧光定量套式RT-PCR,对新疆伊犁地区圈养的100只牧羊犬外周血单核细胞(PBMC)和脑组织(BT)同时进行BDV p24基因片段的检测,并对阳性标本采用GFP-p24、pMD-19扩增后电泳验证,排除质粒污染,并克隆测序,用Fisher精确检验和χ2检验分析两者阳性率的差异。结果牧羊犬外周血单核细胞和脑组织BDV p24检测的阳性率分别为5%和9%;PBMC组和BT组BDV p24检测阳性率差异无统计学意义(P>0.05)。结论BDV在脑内持续感染,但以RT-PCR对外周血单核细胞BDV p24片段的检测有可能替代脑组织BDV检测,作为大规模流行病学调查的手段。     

Persistent infections caused by Borna virus

Summary Pathogenical investigations on Borna disease (enzootic meningoencephalomyelitis of horses and sheep) became possible after we successfully cultivated the virus in cell cultures and adapted the fluorescent antibody technique for the detection of virus antigen and for quantitative assessments. According to our experiences Borna infections occur in two main forms: 1. acute or subacute disease, sometimes in a subclinical form; 2. persistent infection in different forms: a) chronic disease, b) tolerated infection, c) latent infection (possibly). One of the main characteristics of the virus persistence in vivo and in vitro is a relatively short latent phase prior to the continuous virus multiplication in the infected systems. Virus persistence can be demonstrated in the CNS over several months or years in infected animals. Sera from those animals show complement-fixing antibody activity in various amounts during the observation time. In infected cell cultures, the virus likewise persists several months or longer without producing a cytopathic effect. The possibility of vertical virus transmission under field conditions in horses is pointed out. The host spectrum of Borna virus is wide, and potential spread to man is discussed. The persistent form of Borna virus infection in animals and cell cultures sheds new light upon certain aspects of the pathogenesis of Borna disease. Furthermore, the Borna infection may in the future be a useful model for studying slow and persistent virus infections.

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Persistierende Virusinfektionen: Modell Borna

Zusammenfassung Für pathogenetische Studien über die Bornasche Erkrankung (enzootische Menigoencephalomyelitis der Pferde und Schafe) sind alle Voraussetzungen gegeben, seit wir Borna-Virus in der Zellkultur züchten und seinen qualitativen und quantitativen Nachweis mit Hilfe der Immunofluoreszenz-Technik durchführen können. Nach unseren Erfahrungen treten Borna-Infektionen in zwei Hauptformen auf: 1. Akute oder subakute Erkrankung, die auch subklinisch verlaufen kann. 2. Persistierende Virusinfektion. Hierbei müssen wir unterscheiden in a) chronische Erkrankung, b) tolerierte Infektion und möglicherweise c) latente Infektion. Ein Charakteristikum der Viruspersistenz ist sowohl in vivo als auch in vitro die relativ kurze Latenzphase, die der kontinuierlichen Virusvermehrung im Wirtsystem vorausgeht. In infizierten Tieren ist die Viruspersistenz im ZNS über Monate oder Jahre beobachtet worden. Während dieser Zeit enthält das Serum komplementbindende Antikörper in unterschiedlicher Menge. Auch in infizierten Zellkulturen persistiert Borna-Virus über Monate oder länger, ohne daß dabei ein cytopathischer Effekt auftritt. Unter natürlichen Bedingungen besteht beim Pferd die Möglichkeit einer vertikalen Virusübertragung. Das Wirtsspektrum von Borna-Virus ist sehr breit, möglicherweise ist auch der Mensch betroffen. Die persistierende Form der Borna-Virusinfektion wirft neues Licht auf die Pathogenese der Borna-Erkrankung. Darüber hinaus kann sie ein nützliches Modell für das Studium der slow and persistent infections abgeben.

     

Genomic organization of mouse Fc gamma receptor genes.

We have isolated and characterized the gene coding for the mouse Fc receptor that is termed Fc gamma RIIa. The gene contains five exons and spans approximately 9 kilobases. Unlike most members of the immunoglobulin gene superfamily, this gene utilizes multiple exons to encode its leader peptide. The first exon encodes the hydrophobic region of the signal sequence; the second exon, which contains only 21 base pairs, encodes a segment of the signal peptidase recognition site; and the beginning of the third exon encodes the predicted site of peptidase cleavage. The third and fourth exons each code for immunoglobulin-like extracellular domains. The fifth exon encodes the hydrophobic transmembrane domain and the cytoplasmic tail. Partial characterization of the Fc gamma RIIb gene indicates that it also contains multiple leader exons, including a 21-base-pair exon and two exons coding for homologous immunoglobulin-like extracellular domains. However, the Fc gamma RIIb gene uses four exons to encode its intracytoplasmic region. Analysis using contour-clamped homogeneous electric field (CHEF) gels indicates that the Fc gamma RIIa and Fc gamma RIIb genes are linked within 160 kilobases on mouse chromosome 1.     

Identification of alternative splicing and negative splicing activity of a nonsegmented negative-strand RNA virus, Borna disease virus

Borna disease virus (BDV) is a nonsegmented negative-strand RNA virus that belongs to the Mononegavirales. Unlike other animal viruses of this order, BDV replicates and transcribes in the nucleus of infected cells. Previous studies have shown that BDV uses RNA splicing machinery for its mRNA expression. In the present study, we identified spliced RNAs that use an alternative 3' splice site, SA3, in BDV-infected cell lines as well as infected animal brain cells. Transient transfection analysis of cDNA clones of BDV RNA revealed that although SA3 is a favorable splice site in mammalian cells, utilization of SA3 is negatively regulated in infected cells. This negative splicing activity of the SA3 site is regulated by a putative cis-acting region, the exon splicing suppressor (ESS), within the polymerase exon of BDV. The BDV ESS contains similar motifs to other known ESSs present in viral and cellular genes. Furthermore, our results indicated that a functional polyadenylation signal just upstream of the BDV ESS is also involved in the regulation of alternative splicing of BDV. These observations represent the first documentation of complex RNA splicing in animal RNA viruses and also provide new insight into the mechanism of regulation of alternative splicing in animal viruses.     

Genomic organization of rat prolactin and growth hormone genes.

Five overlapping cloned DNAs containing the rat prolactin gene and its flanking sequences, as well as one cloned DNA containing the rat growth hormone gene and its flanking sequences, were isolated from a chromosomal DNA library. They were characterized by restriction enzyme mapping and electron microscopy. In each gene, the structural gene sequence coding for mature mRNA of a length of about 1 kilobase is split into at least five segments by a minimum of four intervening sequences. The two genes are similar in the length and organization of their coding regions, consistent with the suggestion that they are derived from a common ancestral gene. However, the two genes differ greatly in the lengths of their intervening sequences. That leads to a total gene length of 10 kilobase pairs for the prolactin and 2.1 kilobase pairs for the growth hormone gene. At least one intervening sequence appears to be in the 5' nontranslated regions of the prolactin and growth hormone mRNA coding sequences.     

Glial expression of Borna disease virus phosphoprotein induces behavioral and neurological abnormalities in transgenic mice

One hypothesis for the etiology of behavioral disorders is that infection by a virus induces neuronal cell dysfunctions resulting in a wide range of behavioral abnormalities. However, a direct linkage between viral infections and neurobehavioral disturbances associated with human psychiatric disorders has not been identified. Here, we show that transgenic mice expressing the phosphoprotein (P) of Borna disease virus (BDV) in glial cells develop behavioral abnormalities, such as enhanced intermale aggressiveness, hyperactivity, and spatial reference memory deficit. We demonstrate that the transgenic brains exhibit a significant reduction in brain-derived neurotrophic factor and serotonin receptor expression, as well as a marked decrease in synaptic density. These results demonstrate that glial expression of BDV P leads to behavioral and neurobiological disturbances resembling those in BDV-infected animals. Furthermore, the lack of reactive astrocytosis and neuronal degeneration in the brains indicates that P can directly induce glial cell dysfunction and also suggests that the transgenic mice may exhibit neuropathological and neurophysiological abnormalities resembling those of psychiatric patients. Our results provide a new insight to explore the relationship between viral infections and neurobehavioral disorders.     

宁夏地区病毒性脑炎中新发博尔纳病病毒感染的研究

目的 研究宁夏地区新发博尔纳病病毒(BDV)在病毒性脑炎患者中的感染状况,分析病毒株的核酸序列、编码的氨基酸序列和病毒株的系统发生.方法 套式反转录实时荧光定量PCR检测60例病毒性脑炎患者血液标本;并对前期课题组检测的59例病毒性脑炎患者中BDV p24阳性样本和本实验PCR检测阳性标本使用ELISA法检测其对应脑脊液中p40抗体,对阳性标本进行连接测序,应用MEGA和DnaSP4.0软件对测序结果与国外标准株He/80、H1766、strain V等的核酸和氨基酸序列对比分析,构建病毒基因的系统发生树.结果 PCR检测119份血标本,发现有12份标本BDV p24阳性,阳性检出率为10.08%,7份BDV p40检测阳性,阳性率为5.88%;ELISA检测脑脊液核蛋白抗体,有2份阳性,阳性检出率为1.68%.基因聚合分析显示,7份BDV阳性的核酸序列中有6份与德国马源性的He/80株同源性达100%,1份仅有1个碱基发生同义突变;转录后的氨基酸对比分析显示,7份与He/80株完全一致;重构的基因系统发生树中可见宁夏病毒性脑炎患者BDV核苷酸序列与国外标准株形成一个中国(宁夏)-德国-日本的混合支系.结论 宁夏地区病毒性脑炎患者中可能存在BDV感染,其发生可能与动物的密切接触相关,病毒在种系发生中与德国马源性He/80株有极高的同源性,推断病毒有可能从国外传入本土,不排除病毒株变异的可能.