含EGFP基因的马疱疹病毒1型新疆株gE基因缺失株的构建

为筛选马鼻肺炎（equine rhinopneumonitis,ER）基因缺失减毒活疫苗的候选毒株,本研究参考GenBank中EHV-1（登录号：KF644579.1）目的基因序列设计同源臂引物,以本地区流行株XJ2015株DNA为模板PCR扩增gE基因同源臂gEH1、gEH1,以EGFP表达盒（CMV+EGFP+polyA）为标记基因,酶切后依次连接至载体pUC-19,成功构建重组质粒pUC-gEH1H2-EGFP。将XJ2015基因组与质粒pUC-gEH1H2-EGFP共转染至RK-13细胞进行同源重组,以EGFP为标记进行gE基因缺失毒株的筛选及纯化,并测定重组毒株效价。结果显示：经5轮荧光噬斑纯化、PCR及测序鉴定,成功获取一株携带EGFP基因的重组毒株XJ2015-△gE-EGFP,且重组毒株效价（10^7.1TCID₅₀/0.1 mL）较原毒株（10^8.8TCID₅₀/0.1 mL）下降约10^1.7TCID₅₀/0.1 mL。采用同源重组技术成功构建了1株马疱疹病毒1型流行株gE基因缺失突变株,为未来筛选马鼻肺炎基因缺失弱毒疫苗奠定了基础。     

Toll-like receptor activation and expression in bovine alpha-herpesvirus infections

The involvement of Toll-like receptors (TLRs) in bovine herpesvirus types 1 (BoHV-1) and 5 (BoHV-5) infections has not been analyzed. In this study, the role of TLR signaling on virus replication was investigated. Blood leukocytes consistently express TLRs. Thus, our approach was to study in vitro the effects of agonist stimulation of TLRs expressed by peripheral blood leukocytes on BoHV-1 and BoHV-5 replication. Furthermore, the patterns of TLRs 3, 7–9 expression on virus-infected-bovine leukocytes were analyzed. Only Imiquimod (TLR7/8 agonist) showed anti-viral activity on infected MDBK cells. This is the first evidence that the timely activation of TLR7/8 signaling is effective in impairing BoHV-1 and 5 replication, thereby providing an experimental indication that Imiquimod may be a promising immune modulator. This work describes, for the first time, the expression patterns of TLRs in BoHV-1- or BoHV-5-infected-bovine leukocytes, suggesting the involvement of TLR7 and TLR9 in the recognition of these viruses.     

Protein display by bovine herpesvirus type 1 glycoprotein B

Glycoprotein B (gB) of bovine herpesvirus 1 (BHV-1), a major component of the viral envelope, is essential for membrane fusion during entry and cell-to-cell spread. It is cleaved in the trans-Golgi network by the proprotein convertase furin. Integration of the open reading frame (ORF) encoding a mutated gB with a second furin cleavage site and mature boIFN-α as intervening peptide between the amino-terminal (NH₂) and carboxy-terminal (COOH) gB subunits yielded recombinant BHV-1/gB2FuIFN-α which, unexpectedly, express gB with an enlarged NH₂-subunit of 90 kDa. Here we show that boIFN-α-specific antibodies bind to the 90 kDa gB subunit and efficiently neutralize BHV-1/gB2FuIN-α infectivity. We also show that inactivated BHV-1/gB2FuIN-α virions induce an antiviral state in cells incubated with UV-inactivated particles. These results demonstrate that the 90 kDa protein is a NH₂-subunit/boIFN-α fusion protein whose boIFN-α domain is biologically active. To verify that BHV-1 gB is suitable for the display of (glyco)proteins on the surface of virions we constructed BHV-1 recombinants expressing within gB the first 273 amino acids of the NH₂-subunit (HA1) of avian influenza haemagglutinin, either flanked by two furin cleavage sites or with only one cleavage site between a gB/NH₂_HA1 fusion protein and the COOH subunit. The resulting recombinant BHV-1/gB2FuHA1 expressed gB from which 55 kDa HA1 was excised and secreted. In contrast, gB from BHV-1/gB_NH₂HA1 infected cells retained HA1 as fusion protein with the NH₂-subunit. Immunoblotting and neutralization analyses revealed that HA1 is incorporated into the envelope BHV-1/gB/NH₂_HA1 particles and exposed to the exterior of virions. Thus, this novel approach enables display of polypeptides and (glyco)proteins of at least 273 amino acids on viral particles which is of particular interest for development of novel diagnostics and vaccines as well as for, e.g. gene therapy applications especially when biologically active ligands need to be presented.     

鲤科疱疹病毒2型TaqMan荧光定量PCR检测方法的建立

为建立快速和敏感的检测鲤科疱疹病毒2型(CyHV-2)的方法,本研究根据CyHV-2 DNA聚合酶基因序列合成引物和TaqMan探针,建立了CyHV-2荧光定量PCR检测方法.结果显示,以重组质粒为标准品建立的标准曲线在5拷贝/μL～5×108拷贝/μL具有良好的线性关系,相关系数为0.999;其最低检出量为5拷贝/μL,比普通PCR的敏感度高100倍.该方法仅对CyHV-2的靶基因序列进行扩增,而对锦鲤疱疹病毒、流行性造血器官坏死病病毒、病毒性出血性败血症病毒、传染性胰脏坏死病病毒及鲤春病毒血症病毒核酸扩增结果均为阴性.组内和组间重复试验变异系数的平均值分别为0.5％和0.3％,具有良好的重复性.与常规PCR相比较,该方法具有快速、敏感、特异及高通量检测等优点,适用于对CyHV-2的快速检测.     

The epizootology of caprine herpesvirus (BHV-6) infections in goat populations in Greece

Previous preliminary studies had shown that caprine herpesvirus (BHV-6) infections exist in many countries where goats play an economical role. The extensive serum survey made in Greece reveals that the virus must be widespread because more than 50% of the goats have antibodies. The bucks were found to have a higher evidence of infections than the female goats. The kids possessing maternal antibodies became seronegative at the age of 4 months and new antibodies appeared at the age of 7–8 months. Observations in 2 closed goat herds showed that the virus does not spread during the mating and lactating period. Neutralization titres increased or new infections in seronegative animals occurred after the summer when breeding took place. The virus is present in a latent state and recurrent infections are assumed to occur. In spite of that all our efforts to isolate the virus were unsuccessful, even after experimental immunosuppression.     

鸡马立克火鸡疱疹病毒(Fc-126株)的标准化研究 VI.HVT克隆株的稳定性、保存期测定及田间试验效果

对ＨＶＴ克隆株进行了稳定性测定,结果表明克隆株稀释后室温存放１小时,病毒滴度损失不超过３０％,符合有关规定。在－７０℃和－２０℃下保存,克隆株保存期分别至少可达到３年和２．５年。用克隆株试制的３批产品在野外使用效果良好,无任何不良反应。     

Role of the suppressor of cytokine signaling 2 (SOCS2) during meningoencephalitis caused by Bovine herpesvirus 5 (BoHV-5)

The role of suppressors of cytokine signaling (SOCS) in meningoencephalitis caused by Bovine herpesvirus 5 (BoHV-5) was evaluated by intracranial infection in C57BL/6 wild-type mice (WT) and SOCS2 deficient mice (SOCS2^−/−). Both infected groups presented weight loss, ruffled fur and hunched posture. Additionally, infected SOCS2^−/− mice showed swollen chamfer and progressive depression. Infected WT animals developed mild meningitis, characterized by infiltration of mononuclear cells. Moreover, viral DNA was detected in liver and lung from infected WT group. This group also showed elevated brain levels of IFN-γ, IL-10, CXCL1 and CCL5, when compared with non-infected WT animals. Brain inflammation was exacerbated in infected SOCS2^−/− mice with widespread distribution of the virus and increased brain levels of TNF-α, IFN-γ, IL-10, IL-12, CXCL1 and CCL5, when compared with WT infected mice. Moreover, infected SOCS2 deficient mice exhibited reduced brain mRNA expression of IFNα and IFNβ and increased expression of mRNA of SOCS1, compared with infected WT mice. Taken together, our study provides an insight into the role of SOCS2 in modulating the immune response to BoHV-5 infection.