Direct interferon-gamma-mediated protection caused by a recombinant coxsackievirus B3

Coxsackievirus B3 (CVB3) is one of the most important causes of viral myocarditis. Cytokines are involved in the control of CVB3 replication and pathogenesis. Local expression of specific cytokines by recombinant CVB3 confers prevention of virus-caused myocarditis. Expression of IFN-gamma by CVB3(IFN-gamma) protected BALB/c and C57BL/6 mice when the lethal infection with the highly pathogenic CVB3H3 variant was given directly after or prior to CVB3(IFN-gamma) inoculation by decreasing the viral load and spread as well as tissue destruction. This direct effect was not restricted to the homologous virus. In vitro, cocultivation of CVB3(IFN-gamma)-infected cells induced a reduction of CVB3H3 replication and virus-induced cytopathogenicity.     

Characterization of the protective capability of a recombinant coxsackievirus B3 variant expressing interferon-gamma

Several different procedures have been developed to deliver essential genes to an organism by viral vectors. Some reports have already been published demonstrating the potential to use enteroviruses as transfer vehicles. One application of these viral vectors is the organ-specific expression of immunoregulatory cytokines. It has been shown previously that local expression of interferon-gamma (IFN-gamma) by the recombinant coxsackievirus CVB3/IFN-gamma conferred protection against virus-caused disease via direct and indirect mechanisms. Using a murine model of CVB3-induced myocarditis, other aspects of the CVB3/IFN-gamma application as a vaccine were studied concerning route of administration, age, and presence of a pre-existing immune response.     

Expression of cytokine mRNAs in murine hearts with acute myocarditis caused by coxsackievirus B3

In murine acute viral myocarditis, natural killer (NK) cells infiltrate the heart first, followed by activated T-cells, which play an important role in the pathogenesis of the myocardial damage. Because of their multipotential effects, cytokines are thought to play a role in the induction and development of these immune processes. To clarify in more detail the precise mechanism of the cytokine networks involved, the expression of various cytokine mRNAs has been investigated in myocardial cells infected with Coxsackievirus B3 (CVB3) in vivo and in vitro by a semiquantitative polymerase chain reaction (PCR) method. Interleukin (IL)-1α, IL-1β, IL-6, tumour necrosis factor (TNF)-α, and TNF-β were expressed almost throughout the early phase of virus infection with some variations. IL-2, IL-3, IL-4, IL-10, interferon (IFN)-γ, granulocyte/macrophage colony stimulating factor (GM-CSF), and IL-2 receptor (IL-2R) were mainly expressed by the infiltrating cells. TNF-α, TNF-β, and IL-1β were also expressed partly by the infiltrating cells. T-helper (Th)1-related cytokines (IL-2, IFN-γ, and TNF-β) were more strongly expressed than Th2-related cytokines (IL-4 and IL-10) in vivo, indicating that the Th cells which infiltrated the heart and mediated the immune responses in the early phase of acute myocarditis were mainly of Th1-type. © 1997 by John Wiley & Sons, Ltd.     

Genome of coxsackievirus B3

The entire nucleotide sequence of the coxsackievirus B3 strain Nancy (CB3) genome has been determined from cDNA. The genome is 7396 nucleotides long, and encodes a 2185 amino acid long polyprotein. It exhibits the same gene organization as other enterovirus genomes. A detailed comparison was carried out between the proteins encoded by the CB3 and poliovirus type 1 strain Mahoney (PV1) genomes. The genes encoding the VPg polypeptide and the viral polymerase are the most conserved regions. The structural polypeptides VP1, VP2, and VP3 are less well conserved although proline and tryptophan residues frequently are found in identical positions. The VP1 protein of CB3 shows a particularly limited homology in those regions which have been found to induce neutralizing antibodies against PV1. The 5' noncoding region of CB3 is closely related to that of PV1, with regard to both length and sequence organization, whereas the 3' noncoding region of CB3 exhibits some unique features.     

一氧化氮供体和他汀对B组柯萨奇病毒感染的实验研究

目的研究硝酸酯类和他汀类等一氧化氮（NO）供体的抗柯萨奇病毒B组3型（CVB3）的作用及其特点和机制。方法用TCID50和空斑形成实验测定CVB3的毒力；MTT法确定NO供体药物的无毒性浓度；利用细胞病变效应（CPE）抑制实验和空斑形成抑制实验分析NO供体药物对CVB3在HeLa细胞和ECV．304细胞中增殖的抑制作用；并分析硝酸甘油（GRIN）不同给药次数、NO浓度变化以及NO浓度与GTN对CVB3抑制效应间的相关性。结果硝酸酯类药物GTN、硝酸异山梨酯可明显抑制CVB3所致的CPE及空斑形成（P〈0．05），他汀类药辛伐他汀、洛伐他汀均未显示抑制CVB3所致的CPE（P〉0．05）；CVB3接种前预先与GTN作用、CVB3接种同时加入GTN两种条件下CPE抑制率差异无统计学意义（P〉0．05）；CVB3攻击后多次给予GTN的组间CPE抑制率差异无统计学意义（P〉0．05），但在CVB3攻击前不同时间点给予GTN的组间CPE抑制率差异有统计学意义（P〈0．05）；NO浓度与不同时间点给予GrIN的CPE抑制结果呈正相关（r=0．97，P〈0．01）。结论NO供体类药物硝酸酯类具有明确的抗CVB3感染作用，其抗CVB3增殖的作用与NO浓度呈正相关；他汀类药物在本实验条件下未观察到抗CVB3增殖作用，原因可能是细胞类型与他汀不匹配。     

Fungicidal activation of murine macrophages by recombinant gamma interferon.

Alveolar macrophages from BALB/c mice readily phagocytized endospores (2 to 5 micron) and arthroconidia of Coccidioides immitis in vitro. Within 24 to 30 h at 37 degrees C, the phagocytized endospores started developing into spherules, and the arthroconidia formed germ tubes and hyphae. However, these processes did not occur if the macrophages were incubated with murine recombinant gamma interferon (rIFN-gamma) during infection with C. immitis. Treatment with rIFN-gamma activated the fungicidal capabilities of the alveolar macrophages, as evidenced by the 50% reduction in the CFU which could be recovered from macrophages infected in the presence of gamma interferon compared with alveolar macrophages infected without gamma interferon (P less than 0.05). Similar results were seen with peritoneal macrophages incubated with rIFN-gamma and infected with C. immitis. As little as 10 U of rIFN-gamma per ml reduced by half the number of C. immitis CFU which could be recovered from the phagocytes 8 h after infection with arthroconidia, although interferon alone did not affect the viability of the fungi.     

Hyper-IgM1 syndrome with interstitial pneumonia and diarrhea caused by coxsackievirus B4 in a 3-month-old infant.

BACKGROUND: Hyper-IgM1 syndrome is a rare genetic primary immunodeficiency disease caused by mutations of the CD40 ligand gene. It is characterized by normal or elevated levels of IgM and markedly decreased serum IgG, IgA, and IgE levels. Patients with this syndrome often easily develop infections. During the past decade, it has become clear that enteroviral infections may also occur as a manifestation of hyper-IgM1 syndrome. OBJECTIVE: To report a case of hyper-IgM1 syndrome in a 3-month-old boy who had interstitial pneumonia and intractable diarrhea. METHODS: Chest radiography, bronchoscopy, immune studies, and open lung biopsy were performed. RESULTS: Chest radiography revealed diffuse bilateral infiltrates. Immune studies revealed the following proportions of lymphocyte markers: CD3, 5,976/microL; CD4, 5,015/microL; CD8, 866/microL; CD19, 1,325/microL; CD16 + 56, 935/microL; and active T cells, 225/microL. The IgG level was 190 mg/dL; IgA, 2 mg/dL; IgM, 34 mg/dL; IgE, 1 IU/dL; and CH50, 23.8/mL. CD40L expression was less than 1%, and a Tyr 169 Asn (t526a) mutation in the exon 5 tumor necrosis factor domain of the CD40L gene was found. The patient was treated with intravenous immunoglobulin and had a dramatic improvement in symptoms. Open lung biopsy failed to demonstrate pneumocystis, and there was no evidence of cryptosporidium in the stool. However, coxsackievirus B4 was isolated by viral throat culture. CONCLUSION: Interstitial pneumonia and diarrhea caused by coxsackievirus B4 may be a complication of hyper-IgM1 syndrome.     

Molecular epidemiology of a coxsackievirus B3 outbreak.

An outbreak of coxsackievirus B3 infection occurred in South Africa in 1984 with a variety of clinical manifestations being observed. Fifty-one isolates from patients ranging in age from young babies to middle-aged adults were obtained. To define further the epidemiology of this outbreak all isolates were characterised by either 1- or 2-dimensional oligonucleotide mapping. One-dimensional mapping was found to be highly successful for initial screening of the isolates before further characterisation by 2-dimensional fingerprinting. All isolates were found to be essentially the same strain of coxsackievirus B3 although slight variations in both the 1- and 2-dimensional patterns could be observed. Some coxsackievirus B3 strains from geographically unrelated regions but isolated during the same time period as the outbreak showed clearly distinguishable oligonucleotide maps.     

Murine forebrain anomalies induced by coxsackievirus B3 variants

Neonatal or 7-day-old mice inoculated intracranially with either of two temperature-sensitive mutants (tsl, ts6) or the parent coxsackievirus B3 (CVB3) subsequently developed porencephaly or hydranencephaly. The forebrain anomaly induced depended upon age of the animal at inoculation and virus variant inoculated. Sections of brains from hydranencephalic mice revealed severe meningeal reactions, necrotizing encephalitis, and liquifactive necrosis in the cerebrum. No pathology was found in the pons, medulla, or cerebellum. Immunofluorescence studies with hyperimmune anti-CVB3 antiserum showed a random distribution of virus-infected cells in the cerebrum. Virus was recovered from several organs but little to no interferon and no anti-CVB3 neutralizing antibody were present in brain tissues. Availability of cells for replication of virus at the time of inoculation and replicative properties of each virus likely contributed to the outcome. Thus, forebrain anomalies resembling those found in infants can be induced in a murine model by select variants of coxsackievirus B3.     

In vitro activation of murine peritoneal macrophages by recombinant YopJ: production of nitric oxide, proinflammatory cytokines and chemokines

Recently it was reported that 3 μg/ml of recombinant YopJ induced apoptosis in murine peritoneal macrophages in vitro. However, in this study, we report the activation of murine peritoneal macrophages in vitro on treatment with sub-apoptotic dose of recombinant YopJ protein (1 μg/ml). The activation involves enhanced production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), IL-12, and IL-6. Production of NO and IL-6 was found to peak at 24 h of rYopJ treatment, whereas IL-12 and IFN-γ production peaked at 18 h of rYopJ treatment. Increased mRNAs expression of nitric oxide, IL-12, IL-6 and IFN-γ molecules, was also observed in rYopJ-treated macrophages by RT-PCR. rYopJ induced the enhanced activity of protein tyrosine kinases which was inhibited by pharmacological inhibitor genestein, wortmanin and H-7 suggesting the role of tyrosine kinases, PI3K and PKC in the above process. rYopJ also induced increased enhanced production chemokines MIP-1α, MCP-1, and RANTES in macrophages. Significantly, increased expression of TLR-2, TLR-6, MyD 88 and IRAK-1 was also observed by immunoblotting in rYopJ-treated macrophages. rYopJ induced production of NO, TNF-α and IL-6 was significantly inhibited in macrophages pretreated with pharmacological inhibitor wortmanin, genestein and H-7 demonstrating the probable involvement of protein tyrosine kinases in the above process.     

黄芪对心肌炎小鼠心肌穿孔素mRNA和CVB3m mRNA表达的影响

目的探讨黄芪注射液治疗小鼠柯萨奇B3(CVB3)病毒性心肌炎(VMC)的疗效及其机制。方法BALB/c小鼠24只腹腔感染柯萨奇病毒B3亲心肌细胞株(CVB3m)后,随机等分为两组:黄芪治疗组(黄芪注射液每天10g/kg腹腔注射)和对照组。实验第8天留取心肌,分别进行心肌病理检查,心肌穿孔素(perforin,PFP)mRNA和CVB3m mRNA逆转录多聚酶链反应(RT-PCR)分析,并对心肌组织PFP mRNA和CVB3m mRNA表达水平进行相关性分析。结果(1)心肌组织病理改变:黄芪治疗组明显轻于对照组;(2)心肌PFP mRNA表达水平RT-PCR半定量:黄芪治疗组心肌PFP mRNA的表达明显低于对照组(1.10±0.07与1.31±0.12,P<0.01);(3)心肌CVB3m mRNA表达水平RT-PCR半定量:黄芪治疗组心肌CVB3m mRNA表达明显低于对照组(1.07±0.04与1.18±0.02,P<0.01);(4)心肌PFP mRNA水平与CVB3mmRNA水平呈显著正相关(r=0.68,P<0.01)。结论PFP介导的细胞毒性作用在病毒性心肌炎的发病中起重要作用。黄芪对小鼠急性心肌炎模型中心肌组织CVB3m病毒复制有明显的抑制作用,心肌组织中PFP mRNA表达水平与心肌组织CVB3m mRNA的表达水平的变化具有同步性,黄芪对CVB3m诱导的小鼠急性心肌炎模型有显著的治疗作用。     

The activation of caspase-3 and DNA fragmentation in B cells phagocytosed by macrophages

Apoptotic signaling of mammalian cells involves two pathways: the death receptor and mitochondrial pathways. In this in vivo study, we investigated apoptotic signaling of B cells in mouse germinal centers (GCs) of gut-associated lymphoid tissues (GALTs) using transmission electron microscopy (TEM), terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick-end labeling (TUNEL), immunofluorescence of members of caspase family and cFLIP(L), and caspase activity assay. It was very difficult to ultrastructurally differentiate B cells undergoing apoptosis from B cells differentiating into memory cells or plasma cells among B cells constituting GCs. Isolated B cells in GCs showed no active form of caspase-3 or TUNEL immunoreactivity, but expressed cFLIP(L). Contrary to isolated B cells, apoptotic B cells phagocytosed by macrophages exhibited immunoreactivity of the active form of caspase-3 and TUNEL, but lacked the cFLIP(L) expression. The caspase activity assay in GALTs clearly showed intense activity of caspase-3, caspase-9, and caspace-8 that was high in order. Therefore, the death receptor pathway accompanying the increased activity of caspase-3 and caspase-8 may be blocked by the expression of cFLIP(L) in B cells of GALTs. Moreover, both the activation of caspase-3 and DNA fragmentation first occur only when B cells are phagocytosed by macrophages.     

Absence of antiviral activity in recombinant B cell stimulatory factor 2 (BSF-2)

Recombinant B cell stimulatory factor 2 (rBSF-2) did not display any detectable level of antiviral activity when using human diploid fibroblasts, DIP-2, FS-4, FS-7, amnion-derived WISH and FL cells with vesicular stomatitis virus (VSV) and Sindbis virus as challenging agents (less than 2.5 X 10(2) IU/mg). Furthermore anti-IFN-beta could not neutralize the immunoglobulin-inducing activity of BSF-2. Moreover anti-BSF-2 could not neutralize the antiviral activity of IFN-beta. The data indicate that BSF-2 is functionally and immunologically not related to IFNs.     

穿孔素和Fas配体在柯萨奇B3病毒性心肌炎小鼠心肌浸润细胞中表达

目的探讨穿孔素（ＰＦＰ）和Ｆａｓ配体（Ｌ）介导的细胞毒作用在病毒性心肌炎发病中的作用。方法将４０只ＢＡＬＢ／ｃ小鼠随机等分为实验组和对照组，分别用柯萨奇Ｂ３病毒（ＣＶＢ３）及不含病毒的病毒稀释液经腹腔接种，于接种后７天处死，取其心脏。应用免疫组化、逆转录－多聚酶链反应（ＲＴ－ＰＣＲ）和原位杂交等方法，检测细胞介导的细胞毒作用的主要效应分子ＰＦＰ和ＦａｓＬ在心肌浸润细胞中的表达。结果（１）实验组小鼠的心肌组织中均有ＰＦＰ和ＦａｓＬ抗原阳性细胞浸润，对照组则无；（２）ＲＴ－ＰＣＲ检测发现实验组鼠的心肌组织中ＰＦＰ和ＦａｓＬｍＲＮＡ的阳性率均为１００％，明显高于对照组的２０％和３０％（Ｐ均＜０．０１）；（３）原位杂交检查显示，实验组小鼠心肌组织中均可见ＰＦＰ和ＦａｓＬｍＲＮＡ阳性的浸润细胞，而对照组则均未发现。结论ＣＶＢ３小鼠心肌炎急性期，其心肌浸润细胞中有ＰＦＰ和ＦａｓＬ表达，提示它们在病毒性心肌炎发病机制中可能有重要作用     

佐剂LTN增强新型CVB3黏膜疫苗病毒性心肌炎保护效果的机制探讨

Objective To explore the mechanism of lymphotactin(LTN) to exert mucosal adjuvant activity. Methods Complexes of chitosan-pVP1 and chitosan-pLTN were seperately prepared by co-cojugation method, then 50μg(DNA) of each complex was administered intranasally to male BALB/c mice 4times biweekly. Two weeks after the final immunization, mice were challenged with 3LD50 CVB3 to cause viral myocarditis, heart histopathological changes were examined 7 days later. Meanwhile, T cell immune responses, DC percentage and its membrane CD86 expression were monitored in spleen, mesenteric lymph node(MLN) and cervical lymph node(CLN). Results Co-immunizaiton with LTN remarkbly alleviated CVB3-induced cardial injury. This improvement was accompanied with enhanced T cell proliferation and IFN-γ-secreting ability, increased DC frequency and membrane CD86 expression both in spleen and mucosal draining lymph nodes( MLN, CLN). Conclusion LTN exerts its mucosal adjuvant function in augmenting specific T cell immune responses systemically and mucosally via DC enrichment in spleen, MLN and CLN and up-regulation of DC maturation.