传染性法氏囊病病毒VP_2蛋白的分子生物学特性

传染性法氏囊病病毒 (IBDV)主要侵害雏鸡法氏囊等中枢免疫器官 ,其靶细胞是表面带有 Sm Ig的 B淋巴细胞 ,从而导致以淋巴细胞衰竭为特征的免疫抑制性疾病。IBDV属于双节核酸病毒科 (Bir-navirade)禽双节核酸病毒属 (Avibirnavirus)的成员 ,近几年 IBDV分子生物学的研究表明 ,VP2 不仅是 IBDV的主要结构蛋白 ,而且还是主要宿主保护性抗原 ,与病毒中和性抗体的诱导与识别、病毒毒力变异、病毒的抗原漂变、细胞凋亡的诱导等有关 ,因此 VP2 成为研究 IBDV遗传变异、繁殖机制以及IBDV的免疫学防制的“hot”基因。本文就这方面的最…     

传染性法氏囊病病毒VP2蛋白的分子生物学特性

传染性法氏囊病病毒(IBDV)主要侵害雏鸡法氏囊等中枢免疫器官，其靶细胞是表面带有SmIg的B淋巴细胞，从而导致以淋巴细胞衰竭为特征的免疫抑制性疾病。IBDV属于双节核酸病毒科(Birnavirade)禽双节核酸病毒属(Avibirnavirus)的成员，近几年IBDV分子生物学的研究表明，VP2不仅是IBDV的主要结构蛋白，而且还是主要宿主保护性抗原，与病毒中和性抗体的诱导与识别、病毒毒力变异、病毒的抗原漂变、细胞凋亡的诱导等有关，因此VP2成为研究IBDV遗传变异、繁殖机制以及IBDV的免疫学防制的“hot”基因。本文就这方面的最新进展做一综述。     

传染性法氏囊病的流行病学调查

<正>传染性法氏囊病是由传染性法氏囊病病毒(IBDV)引起的,该病毒较为顽固,不像禽流感和新城疫病毒,是有囊膜的病毒,一般的消毒剂可以将其杀灭,相对于IBDV来说显得脆弱一些。IBDV没有囊膜,一旦在鸡场里存在,要想清除并不太容易。有报道指出,IBDV在鸡舍的尘埃     

不同源传染性法氏囊病病毒的分离及其生物学特性分析

用传染性法氏囊病病毒 ( IBDV)单克隆抗体夹心抑制 EL ISA对麻雀、鸭、鹅进行了血清学调查 ,阳性率分别为 7.4% ( 4/ 54 )、95.5%( 3 6 3 / 3 80 )、9.4% ( 1 1 / 1 1 7)。从 IBD阳性麻雀、IBD病鸡以及同群饲养的鸭、鹅体内分离到了 4株不同源病毒 ,IBDV单克隆抗体夹心 EL ISA、Dig-标记 IBDV c DNA探针斑点杂交和交叉中和试验证明该病毒均为 IBDV血清 型。病毒可适应并致死鸡胚 ,适应于鸡胚成纤维细胞并产生细胞病变效应 ( CPE)。病毒代谢抑制试验证明其基因组为 RNA,病毒对乙醚不敏感 ,p H2 .0不能灭活病毒 ,p H 1 2可使病毒失去感染性 ,56℃作用 3 h病毒仍有活性 ,70℃ 1 h可灭活病毒。以上结果表明 ,从鸡、麻雀、鸭、鹅体内分离到的 IBDV生物学性质比较稳定且非常相似。本研究结果提示 IBDV已在我国广泛流行 ,麻雀、鸭、鹅可成为 IBDV携带者或传染源 ,在 IB-DV传播和生态变异中起重要作用     

传染性法氏囊病病毒的培育与变异试验

近年来,传染性法氏囊病病毒(IBDV)毒株毒力不断出现变异,其中也有不少关于中国IBDV变异株的研究报道.为了弄清河北保定流行的IBDV致病性,掌握河北保定地区目前的IBDV流行现状,本试验采集来自河北保定的2个IBDV野毒株进行培育.将这两株IBDV进行病毒核苷酸测定后,再进行同源性的比较研究,用以确定IBDV在河北地区的致病特点与核苷酸的关系.     

传染性法氏囊病的诊断与防控

正在家禽养殖过程中,传染性法氏囊病病毒(IBDV)是家禽养殖中的一个限制因素。IBDV导致的免疫抑制可造成免疫接种失败和鸡继发感染其他病原体。例如,低致病性禽流感病毒在传染性法氏囊病毒(IBDV)感染的鸡体内连续传代时,其毒力会增强。高致病力的IBDV在鸡群中会引起较高的死亡率。     

鸡传染性法氏囊病毒基因组A节段编码前体多聚蛋白的遗传踪迹分析

为研究鸡传染性法氏囊病毒(IBDV)毒力变异的分子机理,本实验采用进化踪迹分析方法对GenBank中登录的28个毒力不同的IBDV参考病毒株的基因组A节段编码的前体多聚蛋白(NH2-pVP2-VP4-VP3-COOH)推导的氨基酸序列进行分析。结果表明超强IBDV与标准IBDV的差异位点集中在第299位、451位、680位、715位和751位氨基酸上;致弱IBDV与标准IBDV的差异位点在第242位、253位、330位和981位氨基酸。该结果为进一步研究IBDV的毒力变异奠定基础。     

传染性法氏囊病病毒基因组A节段3'-UTR对病毒复制影响的研究

为探究传染性法氏囊病病毒(IBDV)基因组A节段3'-UTR是否影响IBDV的复制,本实验应用融合PCR技术将IBDV弱毒Gt株A节段的3'-UTR替换为超强毒Gx株的相应区段,并利用反向遗传操作系统拯救嵌合病毒r Gt-Gx3'UTR,对拯救病毒进行鉴定。结果显示嵌合病毒拯救成功,Gt株的RNA依赖的RNA聚合酶既能识别Gt株的3'-UTR,也能识别超强毒Gx株的3'-UTR。通过比较嵌合病毒与亲本病毒的体外复制曲线,表明3'-UTR能够影响IBDV的复制。3'-UTR二级结构的预测结果表明其可能是以特定的二级结构而非一级序列发挥其功能。本研究为认识IBDV复制特点奠定了基础。     

应用RT／PCR—SSCP法分析传染性法氏囊病病毒的变异性

根据传染性法氏囊病病毒（IBDV）cDNA序列，在病毒VP2区域设计1对引物，应用RT／PCR－SSCP方法对4个不同时间及不同地域从传染性法氏囊病（IBD）病鸡法氏囊组织中分离的IBDV分离物进行了分析，发现4个IBDV分离物的SSCP图谱均存在明显差异，本试验表明，IBDV变异在我国普遍存在，SSCP方法可用于IBDV的变异性分析。     

过氧乙酸戊二醛复方消毒剂对NDV和IBDV的杀灭试验

探讨过氧乙酸戊二醛复方消毒剂杀灭新城疫病毒(NDV)和传染性囊病病毒(IBDV)的效果,为鸡病毒性传染病的防治提供依据。分别采用鸡胚接种法、血凝试验和悬浮杀灭试验测定过氧乙酸戊二醛复方消毒剂对NDV和IBDV的杀灭效果。过氧乙酸戊二醛复方消毒剂灭活NDV、IBDV的有效浓度均为0.04%,最快有效时间分别为10 min和30 min。过氧乙酸戊二醛复方消毒剂可有效杀灭NDV和IBDV。在有效杀灭浓度范围内,随浓度的增高和作用时间的延长对NDV和IBDV的灭活效果增强。     

ie-1和lef-1基因dsRNA表达元件转染及转化细胞对家蚕核型多角体病毒增殖的抑制

通过RNAi介导可以抑制病毒增殖,将相应的RNAi元件通过转基因转入宿主有可能使宿主对病毒产生一定的抗性。根据家蚕核型多角体病毒(BmNPV)基因组中的病毒复制必需基因ie-1、lef-1设计相应的RNA干扰区段,并构建相应的转基因载体转入家蚕BmN细胞中,瞬时表达结果显示转染了转基因RNAi载体的BmN细胞均对BmNPV有一定的抑制作用。IE dsRNA在病毒滴度为10-4时有抑制作用,在病毒滴度为10-5时有比较好的作用;LEF dsRNA则在病毒滴度为10-5时有抑制作用,在病毒滴度为10-6时有较好的抑制作用。通过转基因及G418筛选后,转基因IE dsRNA细胞在病毒滴度为10-4显示出一定的抑制作用,在病毒滴度为10-5表现了明显的抑制作用;而转基因LEF dsRNA细胞在病毒滴度为10-5有一定的抑制作用,但只维持了一个时段。     

Pathogenesis of viral infections

The article considers factors that influence pathogenesis, initiation of infection, dissemination of virus within a host, lytic viral infections, viral immunosuppression, viral immunopathology, and viral oncogenesis.     

病毒受体及其研究现状

受体在宿主细胞与病毒的相互作用中起着极其重要的作用。病毒受体的特性与病毒的宿主范围、组织嗜性有密切关系,是病毒致病性的主要因素之一。病毒受体的研究方法有经典的研究方法,也有现代分子生物学方法。在病毒受体的研究中,通常以分离纯化的细胞膜代替活体细胞来研究病毒受体。通过对病毒与细胞受体相互作用的深入研究,人们已经发现很多受体阻断剂例如植物凝集素和肝素等物质可以阻断病毒与受体的结合,从而为病毒病的防控提供繁殖一些有效的新方法。     

Monoclonal antibody-based immunohistochemical detection of bovine viral diarrhea virus in formalin-fixed, paraffin-embedded tissues.

Thirty-two monoclonal antibodies directed against epitopes on bovine viral diarrhea virus proteins and glycoproteins were tested for immunohistochemical reactivity with bovine viral diarrhea virus in formalin-fixed and paraffin-embedded tissues from 45 cases of bovine viral diarrhea virus-associated mucosal disease. Only one antibody, designated 15C5, which reacts with the 48-kD glycoprotein of bovine viral diarrhea virus, detected an epitope preserved in these specimens. Monoclonal antibody 15C5 and a polyclonal antibody to bovine viral diarrhea virus successfully detected bovine viral diarrhea viral antigens in 44/45 cases of mucosal disease and did not react with formalin-fixed tissues from 30 uninfected cattle. Monoclonal antibody-based immunohistochemical detection of bovine viral diarrhea virus is routinely fixed tissue specimens has advantages over other currently available techniques in terms of the convenience of specimen submission, the relative ease of method standardization, and the rapidity of the test, and by enabling identification of the virus in association with specific tissues, cell types, and histologic lesions.     

牛病毒性腹泻/粘膜病研究进展

牛病毒性腹泻(BVD)是由牛病毒性腹泻病毒(BVDV)引起的一种传染病。被感染后,会导致牛群腹泻、发热、黏膜糜烂溃疡、先天性免疫等症状。本文通过对牛病毒性腹泻流行情况、检测方法、临床类型以及预防与防控等进行论述,为我国的牛病毒性腹泻防治研究提供参考。     

Tissue distribution of Red Spotted Grouper Nervous Necrosis Virus (RGNNV) genome in experimentally infected juvenile European seabass (Dicentrarchus labrax)

The distribution of viral genome in the tissues of juvenile European seabass (Dicentrarchus labrax) during the course of a Red Spotted Grouper Nervous Necrosis Virus (RGNNV) infection has not yet been described. The present study addresses this and indicates which target organs may be involved in viral replication. This information should enable more accurate detection of virus in asymptomatic carriers, and in turn help to control the spread of the disease. The aim of this study was to examine the pattern of expression of viral genomic segments RNA1 and RNA2, using two absolute real-time PCRs (RT-qPCR), over the course of a RGNNV infection after administering the virus by intramuscular injection. In situ hybridization was also used to locate the RNA2 viral segment in different organs throughout the infection. The experimental challenge provoked an acute form of viral nervous necrosis (VNN), with a resulting cumulative mortality of 37%. The RT-qPCRs designed allowed the detection of both genomic segments in all the organs tested (nervous and non-nervous tissues) at all sampling times examined. The highest viral RNA copy number was found in eyes, although viral replication appeared to begin in the brain. Viral replication was also recorded in pooled internal organs and in caudal fin. However, the increase in the viral RNA copy number in these organs did not result in an increased viral titre, which may indicate that a productive infection does not take place in non-nervous tissues, possibly due to a failure in a viral post-replication step.     

Persistent viral infection. The carrier state

A persistent viral infection is one in which the virus in a replicating or non-replicating form persists in the host beyond the normal recovery and elimination period for that particular viral infection. The clinical significance and mechanisms of persistence, when known, are discussed for the important viral infections of dogs and cats. Particular emphasis is given to feline viral rhinotracheitis, feline calicivirus, canine distemper, and feline leukemia.     

Mechanism of protection from primary bovine viral diarrhea virus infection. I. The effects of dexamethasone.

A series of investigations was designed to study the role of cellular immunity and passive antibody in protecting neonatal calves from primary bovine viral diarrhea virus infection. Administration of corticosteroids (dexamethasone) in doses capable of suppressing cellular immunity markedly potentiated systemic bovine viral diarrhea virus infection in calves which lacked bovine viral diarrhea passive neutralizing antibody. Immunosuppressed calves did not form neutralizing antibody to bovine viral diarrhea virus and developed a fatal viremia. Calves with high levels of passive bovine viral diarrhea neutralizing antibodies were protected from the effect of corticosteroids. The results suggest an essential role for humoral passive antibody, but not for cellular immunity, in protection from primary systemic bovine viral diarrhea virus infection in calves.     

The evolution of bovine viral diarrhea: a review

The economic importance of bovine viral diarrhea is increasing with the emergence of seemingly more virulent viruses, as evidenced by outbreaks of hemorrhagic syndrome and severe acute bovine viral diarrhea beginning in the 1980s and 1990s. It appears that evolutionary changes in bovine viral diarrhea virus were responsible for these outbreaks. The genetic properties of the classical bovine viral diarrhea virus that contribute to the basis of current diagnostic tests, vaccines, and our understanding of pathogenic mechanisms are now being reevaluated because of these "new" virus strains. This shift in virulence has confounded both nomenclature and the significance of current bovine viral diarrhea virus categorization. The purpose of this review is to summarize our current understanding of bovine viral diarrhea virus with a chronological review of prevailing scientific tenets and practices as described in clinical and scientific North American veterinary journals and textbooks. The first part of this review describes how we have arrived at our current understanding of the viruses, the diseases, and their nomenclature. The second part of the review deals with current concepts in virology and how these concepts may both explain and predict bovine viral diarrhea virus pathogenesis. By reviewing how knowledge of bovine viral diarrhea has evolved and the theories of how the virus itself is able to evolve, the interpretation of diagnostic tests are more effectively utilized in the control and treatment of bovine viral diarrhea virus associated disease.     

牛病毒性腹泻-黏膜病诊断方法研究进展

牛病毒性腹泻-黏膜病是由黄病毒科、瘟病毒属的牛病毒性腹泻病毒引起的一种传染性疾病。该病以发热、黏膜糜烂、溃疡、白细胞减少、腹泻、怀孕母牛流产或产畸型胎儿为主要特征。该文就近几年来国内外对该病的实验室诊断方法,包括病毒分离、血清学试验、电镜观察、免疫荧光技术、聚合酶链反应技术等的研究概况进行了综述。