感染柯萨奇病毒B3诱导人心肌纤维细胞因子的产生

目的：CVB3感染可导致严重的心脏病，其机制尚不清楚，细胞因子可能有重要作用，但确切来源细胞尚不清楚，心肌纤维细胞是主要间质分子，感染CVB3后检测其细胞因子的产生。方法：采用ELISA方法检测了感染CVB3心肌纤维细胞培养上清液IL－6、IL－8、IL－1α、IL－1β和TNF－α的产生，结果：发现感染CVB3 24小时后IL－6和IL－8即明显升高（P＜0．01），96小时后IL－1α有所升高（P＜0．05），IL－1β和TNF－α无明显变化，结论：IL－6、IL－8、IL－1α在CVB3心肌炎中可能有一定作用。     

Coxsackievirus B3-associated aseptic meningitis: an emerging infection in Hong Kong

Enterovirus (EV) infection is a common disease of childhood and associated not uncommonly with aseptic meningitis. In the summer of 2008, laboratory surveillance has detected increased number of coxsackievirus B3 (CVB3) associated aseptic meningitis in Hong Kong, constituting 11.6% of those infected. This study analyzed the epidemiology, circulating pattern, and clinical presentations of CVB3 in Hong Kong over the last 10 years with reference to the circulation of EV in the locality. Enteroviruses (EV) were isolated from respiratory, cerebrospinal fluid (CSF), stool, and vesicular samples using human rhabdomyosarcoma, human laryngeal carcinoma (HEp2-C), human lung fibroblast (MRC-5), and African green monkey kidney (Vero) cell lines. Virus isolates were identified and characterized by indirect immunofluorescence (IF) using monoclonal antibodies (mAB), neutralization test as well as partial VP1 sequencing. Different from previous years, IF test result showed that majority of the isolates from 2008 were untypeable by the mAB suggesting antigenic change. Sequence analysis revealed that these isolates were clustered with recent isolate from Fuyang, China. Review of data from 1999 to 2008 showed increased activity of CVB3 in the years 2005 and 2008, and isolates in these 2 years displayed an amino acid change from threonine to alanine at codon 277 of the VP1 gene, which may be associated with central nervous system (CNS) disease.     

Coxsackievirus B3 infection induces anti-flavoprotein antibodies in mice

Enteroviruses, the most common cause of acute myocarditis, are also supposed aetiological agents of dilated cardiomyopathy. Autoantibodies (anti-M7; Klein & Berg, Clin Exp Immunol 1990; 58:283-92) directed against flavoproteins with covalently bound flavin (alphaFp-Ab; Otto et al., Clin Exp Immunol 1998; 111:541-2) are detected in up to 30% of sera of patients with myocarditis and idiopathic dilated cardiomyopathy (IDCM). Mice inoculated with a myocarditic variant of coxsackievirus B3 (CVB3) were employed to study the occurrence of serum alphaFp-Ab following viral infection. The presence of alphaFp-Ab was analysed by Western blotting with the flavoprotein antigens 6-hydroxy-D-nicotine oxidase (6HDNO) and sarcosine oxidase (SaO). Of 10 sera from CVB3-infected mice, five showed a strong reaction with both antigens. The sera were reactive also to the mitochondrial covalently flavinylated proteins dimethylglycine dehydrogenase and sarcosine dehydrogenase. Sera of non-infected mice did not react with these antigens. A 6HDNO mutant protein with non-covalently bound FAD no longer reacted on Western blots with sera of CVB3-infected mice. Preincubation with FAD abolished or reduced the reaction of the sera with the 6HDNO antigen. At 2 weeks p.i. the alphaFp-Ab were of the IgM and IgG isotypes, at 7 and 9 weeks p.i. of the IgG isotype. The sera of CVB3-infected mice reproduced closely the antigenic specificity of the anti-M7 sera of patients, lending further support to the role of coxsackieviruses in the pathogenesis of IDCM.     

Coxsackievirus B3-induced chronic myocarditis in outbred NMRI mice

OBJECTIVES: The pathogenesis of coxsackievirus B3 (CVB3)-induced myocarditis was investigated in adult Han:NMRI mice. The outbred model, in comparison with inbred models, represents better the natural variable susceptibility of the human population. STUDY DESIGN/METHODS: We analyzed the replicating virus titer, the antibody response in the acute and chronic phase of disease, the histology of myocardial injury, and the persistence of viral RNA. RESULTS: NMRI mice infected with 5000 plaque-forming units (PFU) of the CVB3 variant "P"D, a lytic variant to human fibroblast lines, showed a peak of virus replication at day 14 and developed a severe acute myocarditis. The chronic myocarditis was characterized by progressive fibrosis, small foci of infiltrates, persistent viral RNA in the heart, and detectable anti-CVB3 IgG production and neutralizing antibody response up to day 98 postinfection. CONCLUSIONS: CVB3"P"D is able to induce chronic myocarditis in NMRI mice. This model provides a method for examining and proving the mechanisms of myocardial pathogenesis and of developing therapeutic strategies.     

Coxsackievirus B3-induced myocarditis in MHC class II-deficient mice

OBJECTIVES: The pathogenesis of coxsackievirus B3 (CVB3)-induced myocarditis was investigated in immunocompetent C57BL/6 and MHC class II knockout mice with identical genetic backgrounds. STUDY DESIGN/METHODS: We analyzed the histology and immunohistology of myocardial injury, the replicating virus titer, and antibody response in the early and late phase of disease. RESULTS: CVB3-infected C57BL/6 mice showed acute myocarditis, with spontaneous healing, virus elimination, anti-CVB3 IgM/IgG production, and neutralizing antibody response. In contrast, MHC class II knockout mice developed less severe acute myocarditis, persistence of infiltrations and strong fibrosis, virus persistence, and weak IgG response, with absence of virus neutralizing antibodies. CONCLUSIONS: Immunodeficient organisms are more susceptible to long-term heart muscle injuries after infection with CVB3. The presence of CD4+ T cells are necessary to prevent the development of chronic disease.     

表达海肾荧光素酶的重组柯萨奇病毒B组3型质粒的构建及鉴定

目的 构建能表达荧光素酶的重组柯萨奇病毒B组3型(coxsackievirus B3,CVB3),以实现定量检测CVB3.方法 将荧光素酶基因克隆至CVB3基因组开放读码框起始位置,重组病毒基因组DNA转染HeLa细胞以恢复病毒、测序,评价重组病毒的荧光素酶表达,扩增重组病毒并测定重组病毒株毒力.结果 成功构建2个重组病毒质粒,转染HeLa细胞,表达海肾荧光素酶(humanizedform of Renilla Luc,hRLuc)、荧火虫荧光素酶(firefly luciferase,Luc)的pCVB3-hRLuc和pCVB3-Luc转染后第1代均可检测到hRLuc和Luc活性,但只有pCVB3-hRLuc转染细胞有明显细胞病变.扩增和纯化的CVB3-hRLuc病毒感染HeLa细胞可见明显细胞病变及hRLuc活性.扩增的CVB3-Luc没有观察到明显的细胞病变,且从第2代病毒开始就未能检测到荧光素酶活性.用HeLa细胞经空斑形成试验进行毒力测定,CVB3-hRLuc的毒力为1.4(107 pfu/ml).结论 成功构建了表达hRLuc的重组CVB3毒株CVB3-hRLuc,为定量研究CVB3感染打下基础.     

人衰变加速因子的二级结构与B细胞表位预测

目的分析预测人衰变加速因子的二级结构特征及B细胞表位。方法比较Chou&Fasman经典方案和基于多重序列比较的PHDsec二级结构预测方案的预测准确率,应用较优方案对DAF的二级结构进行预测分析;运用Hopp&Woods的亲水性方案及PHDacc可及性方案预测DAF的亲水性和可及性,结合DAF的二级结构特征,分析预测DAF的B细胞表位。结果PHDsec方案对SCR的预测准确率明显高于Chou&Fasman方案,DAF的SCR1-4中无α螺旋,仅包含β折叠及袢;推测最可能的抗原表位位于Pro73-Val79、Arg130-Leu139及Glu156-Cys163;SCR1、SCR2与SCR3、SCR4在亲水性及二级结构分布方面具有较大差异。结论研究的分析预测结果将有助于确定DAF的B细胞表位及其生物学活性部位。     

Detection of Coxsackievirus B3 RNA in myocardial tissues by the polymerase chain reaction.

Coxsackievirus B3 is a possible etiologic agent in some forms of myocarditis and idiopathic dilated cardiomyopathy. A method for the detection of coxsackievirus B3 RNA was developed using the polymerase chain reaction based on the amplification of a cDNA copy of the positive-strand viral RNA. The fidelity of the method was established in two murine models for coxsackie B3 myocarditis. All cardiac specimens with adequate RNA for study from coxsackie B3-infected mice contained detectable viral RNA, in contrast to none of control specimens from noninfected mice. The sensitivity of the technique was established at approximately 1 to 100 plaque-forming units of virus per gram of tissue, and the specificity was established as limited to the coxsackievirus B3 serotype among nine viruses tested. In patients with myocarditis, one of five specimens contained detectable viral RNA, whereas none of 11 specimens from patients with idiopathic dilated cardiomyopathy or 21 myocardial specimens from patients with a wide variety of other cardiac disorders contained detectable coxsackie B3 viral RNA. The results show that the polymerase chain reaction is a useful means for detecting coxsackie viral RNA and its application should help in the evaluation of hypotheses concerning the infectious etiology of human myocarditis and idiopathic dilated cardiomyopathy.     

Role of interferon in lethality and lymphoid atrophy induced by Coxsackievirus B3 infection in mice.

To assess the importance of interferon (IFN) in the pathology of coxsackievirus B3 (CVB-3) infection, we evaluated both mortality rate and lymphoid involution in young adult BALB/C mice infected with lethal doses of the virus and treated either with anti-IFN antibody or with murine IFN-alpha/beta. Administration of antibody to IFN caused a profound worsening of the pathology and an increase in the mortality rate in infected animals. Treatment with murine IFN exerted a significant ameliorative effect on lethality when administered concomitantly with or soon after virus infection. The extent of this protection was correlated with the plasma levels of exogenous or endogenous IFN at 6 h postinfection, whereas no correlation with IFN titers was found later. The effects of IFN apparently were not directly mediated by antiviral effects, because at the times studied, no relation was found between IFN levels and virus titers, at least in the plasma of the infected animals. Lymphoid atrophy, assessed by measuring spleen weight, was only partially reversed by early IFN treatment. These data suggest that IFN production is critical during the early phases of infection, whereas it does not seem to play a significant protective role at later stages.     

Inhibition of nuclear factor kappa B activation reduces Coxsackievirus B3 replication in lymphoid cells

Interactions between viral replication machineries and host cell metabolism display interesting information how certain viruses capitalize cellular pathways to support progeny production. Among those pathogens, Coxsackievirus B3 (CVB3) has been identified to manipulate intracellular signaling very comprehensively. Next to others, this human pathogenic virus causes acute and chronic forms of myocarditis, pancreatitis, and meningitis. Here, activation of nuclear factor kappa B (NFκB) signaling appears to be involved in successful infection. Viral replication is not restricted to solid organs but involves susceptible immune cells as well. In the present study, p65 phosphorylation as one aspect of NFκB activation and inhibition via BAY 11-7085 administration was analyzed in the context of CVB3 replication in lymphoid cells. During CVB3 infection, an up-regulation of p65 translation is detectable, which is accompanied by noticeable phosphorylation. Inhibition of NFκB signaling reduces viral replication in a dose- and time-dependent manner. Taken together, these results indicate that during CVB3 replication in human and murine lymphoid cells, NFκB signaling is activated and facilitates viral replication. Therefore, antiviral strategies to target such central cellular signaling pathways may represent potential possibilities for the development of new virostatica.     

Coxsackievirus B3 persistence and myocarditis in NFR nu/nu and +/nu mice

NFR nude (nu/nu) and euthymic (+/nu) littermates were infected with coxsackievirus B3 (CBV-3) and assayed for virus persistence in the heart, pancreas and spleen, for development of myocarditis and for antibody production. The virus grew to higher titer and persisted longer in hearts of nu/nu mice. In both types of mice there was comparable myocarditis with a mononuclear cell inflammatory response, and there was some evidence of chronic lesions for up to 21 days in +/nu and 28 days in nu/nu mice. Antibody of the IgM class was present at 7 days in both strains of mice. Thereafter, +/nu mice produced high titers of virus-specific IgG antibody, while nu/nu mice produced little or no viral IgG antibody. The persistence of virus for up to 28 days in NFR nude mice is longer than has been reported previously, and offers an opportunity for further study of the role of T-cells in virus persistence and myocarditis.     

Coxsackievirus B3 replication and persistence in intestinal cells from mice infected orally and in the human CaCo-2 cell line

Although the transmission of coxsackievirus B3 occurs mainly via the oral route, little is known about the primary replication and persistence of this agent in the intestine. To address this question, BALB/c mice were inoculated by gavage with coxsackievirus B3, Nancy strain. The mice were killed from 1 hr to 90 days after infection. The viral markers were detected in the small intestine using RT-PCR, cell culture and detection of VP1 protein. Coxsackievirus B3 was detected positive by the three methods from hr 2 to day 45 after infection. By using monoclonal antibodies directed towards VP1, CD40 and CD26, the virus was shown to be present in the lymphocytes of the mucosa as soon as 2 hr after infection; in contrast, no virus was detected in the epithelial cells lining the intestinal lumen. Further experiments were performed to evaluate the capacity of coxsackievirus B3 to establish a persistent infection in two intestinal cell lines. In contrast to HT29 cells, the CaCo-2 cells were shown to develop a persistent infection for up to 20 passages, as demonstrated by the detection of viral RNA and VP1 protein. This study provides further evidence that, after infection by the oral route, the viral particles are concentrated in the lymphocytes of the mucosal layer. In addition, the results suggest that coxsackievirus B3 is capable of establishing a persistent infection in the small intestine that may act as a reservoir of viral particles for the delayed spread of the virus to other target organs.     

Cellular immune responses in mice challenged with an amyocarditic variant of Coxsackievirus B3

An amyocarditic variant of a temperature-sensitive (ts) mutant derived from the parent myocarditic variant Coxsackievirus B3 (CVB3m) was studied in a murine model of CVB3m-induced myocarditis to assess virus-induced antigens and their possible role in the disease process. Amyocarditic variant ts5R induced a heart tissue antigen(s), extractable by hypertonic KC1, which inhibited migration of peritoneal exudate cells from CVB3-inoculated myocarditic mice in an agarose droplet cell-migration-inhibition assay. The ts5R variant was amyocarditic at inoculum doses of 10(3) to 10(8) plaque-forming units per mouse, but in cyclophosphamide-immunosuppressed mice, ts5R induced myocarditis. Viable ts5R served as a vaccine and protected mice against CVB3m-induced myocarditis. Murine neonatal skin fibroblasts (MNSF) infected with either virus served as in vitro targets and were lysed by splenic cytotoxic T lymphocytes from mice inoculated with either virus variant. ts5R and CVB3m replicated to similar titers in murine neonatal skin fibroblasts (MNSF) at 24 hr postinoculation (pi), but differences in titers were found by 72 hr pi. Levels of natural killer cell activities in spleens of ts5R-inoculated mice were slightly lower than in spleens of CVB3m-inoculated mice at 7 days pi. The data suggest that viral induction of new antigens on target cells and viral induction of specific cytotoxic T lymphocytes that recognize these antigenic changes do not always result in induction of myocarditis.     

Immunization of mice against Coxsackievirus B3 and prevention of foetal growth retardation.

Coxsackievirus B3 infection in pregnant mice leads to a severe pancreatitis with a retardation of foetal growth and increased wastage. The present study demonstrates that animals may be immunized actively or passively against this infection to allow foetal development to proceed normally. Active immunization was achieved by injecting a low dose of live virus into 4-week-old animals. These mice were then mated at 10 weeks and given a high dose of virus on the eighth day of pregnancy. Examination at 18 days'' gestation revealed that foetal growth was not significantly different from the controls injected with heat-killed virus, and pathological changes in the mothers were not seen. Animals were passively immunized against Coxsackievirus B3 in pregnancy by injecting serum from immunized animals 1 day before the high dose of live virus was given. This procedure also protected against the effects of the virus and litter sizes and foetal weights were normal.     

Coxsackievirus infection of mice. I. Viral kinetics and histopathological changes in mice experimentally infected with coxsackieviruses B3 and B4 by oral route

We followed the viral kinetics and histopathological changes in different organs of immunocompetent mice infected orally with coxsackieviruses B3 (CVB3) Nancy strain and B4 (CVB4) JVB strain separately. The viruses used were not adapted to mouse organs. In the acute phase of infection, the viral kinetics indicated virus replication in the heart, spleen, thymus, pancreas, and small and large intestines. This was accompanied by histopathological changes, mild infiltration of mononuclear cells and fibrosis in the heart. The necrotic changes with mononuclear infiltration and fibrosis in the myocard was observed on days 56 and 71 p.i. in the CVB4-infected animals only. In the mice infected with CVB3 and CVB4 a prolonged presence of infectious virus was shown in the spleen and small intestine; in the latter viral antigen was localized in smooth muscles of the muscular wall immunohistochemically. This is the first report on prolonged replication of coxsackieviruses (CV) in the spleen and small intestine in orally infected mice.     

柯萨奇B3病毒诱导小鼠单核-巨噬细胞产生肿瘤坏死因子和白细胞介素6

观察柯萨奇Ｂ３（ＣｏｘＢ３）病毒对小鼠单核－巨噬细胞（Ｍｏ／Ｍφ）的感染，及诱导白细胞介素６（ＩＬ－６）和肿瘤坏死因子（ＴＮＦ）的产生。发现ＣｏｘＢ３能够感染小鼠腹腔巨噬细胞，并释放感染性病毒颗粒；一定感染量病毒的感染，对Ｍｏ／Ｍφ的存活率无明显影响。在体内和体外实验中，ＣｏｘＢ３的感染均可明显诱导Ｍｏ／Ｍφ释放单核因子，在受染的Ｍｏ／Ｍφ培养上清液中及ＣｏｘＢ３感染急性期小鼠血浆和心肌匀浆液中均可测到ＩＬ－６和ＴＮＦ浓度明显升高。     

DAF与CD3协同刺激人外周血T细胞活化的实验研究

目的：探讨人促衰变加速因子（decay-accelerating factor,DAF)作为共刺激分子参与T细胞活化的作用机制。方法：观察3株针对DAF不同SCR的单抗单独使用或者与抗人CD3单抗联合使用时，对人外周血T细胞增殖、IL－2分泌以及胞浆Ca^2 水平的影响。结果：所用3株抗人DAF单抗不能活化T细胞，而抗人DAF单抗与抗人CD3单抗可以协同刺激T细胞增殖，促进IL－2分泌以及提高胞浆Ca^2 水平。结论：抗人DAF单抗与抗人CD3单抗可协同刺激人外周血T细胞活化。     

Coxsackievirus B3-induced acute pancreatitis: analysis of histopathological and viral parameters in a mouse model.

Coxsackievirus B3 infection in mice was studied histopathologically, by virus isolation and by nucleic acid hybridization after intraperitoneal inoculation of the virus. Extensive viraemia was detected for 1-3 days post-infection. All mice developed necrotizing acute pancreatitis and focal myocarditis. Pancreatitis eventually lead to complete atrophy of the exocrine pancreas. However, the islets of Langerhans and pancreatic ducts remained morphologically intact. Virus could be demonstrated in pancreatic tissue for 1-5 days post-infection by in-situ and spot hybridization as well as by virus isolation. Virus was not detectable on days 7-22 post-infection suggesting an autodigestive aetiology in further destruction of the exocrine pancreas. The mouse model described here permits detailed analysis of viral and host factors in the pathogenesis of enterovirus infections. Since coxsackie B viruses have been proposed to be aetiological agents in human acute pancreatitis, the application of in-situ hybridization allows analysis of enteroviruses directly from pancreatic tissue of clinical routine specimens.