Characterization of bovine herpesviruses isolated from six sheep and four goats by restriction endonuclease analysis and radioimmunoprecipitation

Viral DNA from 10 herpesviruses isolated from 6 sheep and 4 goats were examined by restriction endonuclease analysis with respect to their relatedness to one another; to bovine herpesvirus type 6 (BHV-6), also known as caprine herpesvirus; and to 2 strains of bovine herpesvirus type 1 (BHV-1), known as infectious bovine rhinotracheitis virus (IBRV) and infectious pustular vulvovaginitis virus (IPVV). Viral proteins from the isolates were examined by radioimmunoprecipitation with anti-BHV-1/IBRV gnotobiotic calf (bovine) serum, anti-BHV-1/IBRV bovine hyperimmune serum, and anti-BHV-6 rabbit serum to evaluate their antigenic relatedness to each other. The goat isolates were obtained from animals with various disease conditions including respiratory tract disorders, vulvovaginitis, and wart-like lesions on the eyelid. The other isolates were from domestic sheep and came from aborted fetuses or from sheep with fatal pneumonia or proliferative lesions around lips and nose. All of the goats and 4 of the sheep from which the viral isolates were obtained had comingled with cattle. Purified DNA from each of the 10 field isolates and from BHV-1/IBRV, BHV-1/IPVV, and BHV-6 caprine herpesvirus was cleaved with restriction endonuclease Pst I. Five of 6 sheep isolates and 3 of 4 goat isolates yielded unique restriction patterns, ie, patterns that differed from each other by one or more bands. Sheep isolate DNA patterns were different from goat isolate patterns, and all restriction endonuclease analysis patterns were similar to the pattern for BHV-1/IBRV, but different from that for BHV-1/IPVV or for BHV-6.(ABSTRACT TRUNCATED AT 250 WORDS)     

Restriction endonuclease analysis of infectious laryngotracheitis viruses: comparison of modified-live vaccine viruses and North Carolina field isolates

Six modified-live (ML) infectious laryngotracheitis (ILT) vaccine viruses, three reference strains, and 18 field isolates were compared by restriction endonuclease analysis of their DNA. Viral DNA digestion patterns were established for vaccine viruses using restriction endonucleases PstI, BamHI, KpnI, and HindIII. Using these enzymes, five of six ML vaccine viruses had identical restriction endonuclease cleavage patterns. Vaccine viruses had distinct patterns compared with ILT virus reference strains Illinois-N71851, Cover, and NVSL. Restriction endonuclease cleavage patterns of 18 field isolates of ILT virus, obtained from ILT outbreaks in North Carolina, were indistinguishable from vaccine viruses. These results suggest a possible role of vaccine or vaccine-like viruses in recent ILT outbreaks.     

牛传染性鼻气管炎疫苗的研究进展

牛传染性鼻气管炎(infectious bovine rhinotracheitis,IBR)是由牛传染性鼻气管炎病毒(infectious bovine rhinotracheitis virus,IBRV)即牛疱疹病毒1型(BoHV-1)感染所引起的一种高度接触性传染病。该病给我国养牛业带来了巨大的经济损失。由于缺乏有效的治疗性药物,疫苗免疫仍然是防控该病的有效措施。当前,牛传染性鼻气管炎疫苗主要包括灭活疫苗、弱毒疫苗2种常规疫苗和亚单位疫苗、DNA疫苗、IBRV基因缺失疫苗、病毒活载体疫苗4种基因工程疫苗,各种疫苗各有优点。现对上述疫苗的最新研究进展进行综述,以期为IBRV疫苗的研究与开发提供参考。     

A comparison of polypeptides and restriction endonuclease sites of BHV-1 isolates and identification of IPV virus in Japan

Bovine herpesvirus 1 (BHV-1) isolates from respiratory tract and from vagina of bovine in Japan were analyzed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and the DNA restriction endonuclease cleavage pattern, and compared with European BHV-1 strains. Both protein profile and DNA cleavaged pattern of BHV-1 isolates from respiratory tract were the same as those of European infectious bovine rhinotracheitis (IBR) virus, whereas the protein profile and DNA cleavage patterns of one isolate (M1) from vagina was the same as those of the European infectious pustular vulvovaginitis (IPV) virus. The facts indicate that IPV virus has existed in Japan.     

Efficacy of viral components of a nonabortigenic combination vaccine for prevention of respiratory and reproductive system diseases in cattle

Efficacy and safety of components of an IM-administered vaccine for prevention of infectious bovine rhinotracheitis virus (IBRV), parainfluenza type-3 (PI-3) virus, bovine viral diarrhea virus (BVDV), and respiratory syncytial virus (RSV) infections and campylobacteriosis and leptospirosis were evaluated in cattle, including calves and pregnant cows. Challenge of immunity tests were conducted in calves for IBRV, PI-3 virus, or BVDV vaccinal components. All inoculated calves developed serum-neutralizing antibodies and had substantially greater protection (as measured by clinical rating systems) than did controls after challenge exposure to virulent strains of IBRV, PI-3 virus, BVDV, or RSV. In in utero tests, IBRV or bovine RSV vaccinal strains were inoculated into fetuses of pregnant cows. Histologic changes or abortions did not occur after fetal inoculation of the RSV vaccinal strain, and 10 of 14 fetuses responded serologically. Of 9 fetuses, one responded serologically to the IBRV vaccinal strain after in utero inoculation and was aborted 3 weeks later. In an immunologic interference test, 10 calves vaccinated with 2 doses of the multivalent vaccine, containing the 4 viral components and a Campylobacter-Leptospira bacterin, developed serum-neutralizing antibodies to IBRV, PI-3 virus, BVDV, and RSV without evidence of serologic interference. Under field conditions, 10,771 cattle, including 4,543 pregnant cows, were vaccinated. Vaccine-related abortions did not occur.     

Comparative serological response in calves to eight commercial vaccines against infectious bovine rhinotracheitis, parainfluenza-3, bovine respiratory syncytial, and bovine viral diarrhea viruses

A field trial was conducted to compare the serological responses in calves to eight commercial vaccines against infectious bovine rhinotracheitis virus (IBRV), parainfluenza-3 virus (PI3V), bovine respiratory syncytial virus (BRSV), and/or bovine viral diarrhea virus (BVDV). Calves given IBRV, P13V, BRSV, and BVDV vaccines had significantly higher antibodies to these viruses than unvaccinated controls; however, serological responses to killed BVDV vaccines were low. Calves with preexisting antibodies to IBRV, PI3V, BRSV, and the Singer strain of BVDV had lower seroconversion rates following vaccination than calves that were seronegative initially.

Serological responses in calves to IBRV, PI3V, BRSV, and BVDV differed among various commercial vaccines. Antibody titers to IBRV were higher in calves vaccinated with modified-live IBRV vaccines than in those vaccinated with killed IBRV vaccines. Following double vaccination with modified-live IBRV and PI3V vaccines, seroconversion rates and antibody titers to IBRV and PI3V were higher in calves vaccinated intramuscularly than in those vaccinated intranasally. Calves given Cattlemaster 4 had significantly higher titers to BRSV and PI3V, and lower titers to BVDV, than calves given Cattlemaster 3, suggesting that the addition of BRSV to Cattlemaster 4 caused some interaction among antigens.

     

牛传染性鼻气管炎疫苗研究进展

牛传染性鼻气管炎(IBR)是由牛传染性鼻气管炎病毒(IBRV)感染家养牛引起的一种热性接触性传染病。由于缺乏有效的治疗性药物,因此疫苗免疫仍然是防控该病的关键措施。针对该病常用的疫苗主要有灭活疫苗和活疫苗,而基因缺失活疫苗由于具有免疫标识,已成为新型疫苗研发的主流方向。一些发达国家已利用基因缺失标记疫苗,如IBRV gE缺失疫苗,进行免疫根除计划并净化了该病。然而,由于现存的疫苗仍存在免疫抑制与潜伏感染等问题,亟需研制更有效的标记疫苗。论文就牛传染性鼻气管炎病毒的病原学特征、免疫抑制及疫苗研发进展进行综述,以期为IBR有效疫苗的研发及其在防控上的应用提供参考。     

Differentiation of vaccine strains and Georgia field isolates of infectious laryngotracheitis virus by their restriction endonuclease fragment patterns

Seven restriction endonucleases (REs) were used to cleave the DNA from seven vaccine strains of infectious laryngotracheitis (ILT) virus and from six Georgia field isolates of ILT virus. After electrophoresis of the resulting RE fragments, the patterns were compared in order to differentiate strains of ILT virus. The six chicken-embryo-origin (CEO) vaccines were identical with each RE, but the tissue-culture-origin (TCO) vaccine strain differed from the CEO vaccines using five of the REs. Four of the six field isolates were identical by each RE, but two field isolates differed from each other and from the four identical field isolates on the basis of patterns produced by some but not all of the REs. The four identical field isolates could not be differentiated from the CEO vaccine strains by any RE, but the other two field isolates were not identical to either strain of vaccine virus. This work demonstrates that differentiable strains of ILT virus exist in the United States and that viruses other than vaccine viruses are involved in field outbreaks of ILT.     

奶牛传染性鼻气管炎病毒gG基因PCR检测方法的建立

本试验旨在建立一种PCR技术,既能快速检测牛传染性鼻气管炎病毒,又能区分同属病毒牛疱疹病毒5型和伪狂犬病病毒。根据基因库中牛传染性鼻气管炎病毒gG基因的特异性引物,建立PCR方法,对牛传染性鼻气管炎病毒参考毒株和阳性样本进行扩增,结果均能扩增出一条463 bp的特异性条带;对同属的牛疱疹病毒5型进行扩增,获得651 bp和431 bp两条带;对同属伪狂犬病病毒进行扩增,获得493 bp的条带;而非相关病毒(如猪呼吸与繁殖综合征病毒等),不能扩增出条带。对牛传染性鼻气管炎病毒的检测灵敏度为2×10^-3 PFU/mL。鉴于该方法具有良好的灵敏度和特异性,将在牛疱疹病毒感染诊断和标记疫苗免疫后的鉴别诊断方面具有良好的应用前景。     

Differentiation of avian adenovirus type-II strains by restriction endonuclease fingerprinting

Three serologically indistinguishable viruses from the avian adenovirus type-II splenomegaly virus of chickens, marble spleen disease virus of pheasants, and hemorrhagic enteritis virus of turkeys, were analyzed by restriction endonuclease fingerprinting. The DNA from these viruses were examined with 6 restriction endonucleases (Bgl II, EcoRI, HindIII, Hha I, Xho I, and BamHI). Markedly different DNA cleavage patterns were found in these virus isolates with all the 5 enzymes, except with BamHI, suggesting genetic differences between isolates of adenovirus type II. Restriction endonuclease analyses were found to provide a method for distinguishing genetically different, and yet serologically similar, strains of avian adenovirus type II.     

Virulence of infectious laryngotracheitis viruses: comparison of modified-live vaccine viruses and North Carolina field isolates

Virulence of six modified-live (ML) infectious laryngotracheitis (ILT) vaccine viruses was compared with that of 11 field isolates (indistinguishable from vaccine viruses by DNA restriction endonuclease analyses) by intratracheal exposure of 4-week-old, specific-pathogen-free chickens. Virulence of ILT viruses was based on an intratracheal pathogenicity index, mortality, and tracheal lesions. Intratracheal pathogenicity indices for ML vaccine viruses ranged from 0.0 to 0.14, while those for field isolates were 0.20 to 0.82. Mortality was a consistent clinical feature of field isolates; all produced mortality, with seven of the 11 isolates causing two or more deaths per inoculation group. In contrast, only one of six ML vaccine viruses produced mortality (one death per inoculation group). In general, tracheal lesions were more severe in chickens inoculated with field isolates and were produced more consistently than in chickens inoculated with vaccine viruses. These studies indicate that virulence of ILT field isolates was greater than that of ML vaccine viruses. Together with previous restriction endonuclease analyses, these findings suggest the possibility that field isolates originated from ML vaccine viruses through reversion to parental-type virulence.     

A specific PCR to differentiate between gE negative vaccine and wildtype bovine herpesvirus type 1 strains

In the context of infectious bovine rhinotracheitis (IBR) control programmes using glycoprotein E (gE) deleted marker vaccines, a PCR assay was developed to allow the genotypic differentiation between wildtype bovine herpesvirus type 1 (BoHV-1) and gE negative strains. This assay is based on the PCR amplification of a 281 bp DNA fragment within the gE gene. The specificity of the amplification was confirmed by restriction endonuclease analysis and nucleotide sequencing of the PCR product. Its ability to determine the gE genotype of BoHV-1 strains was demonstrated on isolates coming from 20 experimental calves infected with four different BoHV-1 strains. This PCR assay may be a useful tool for monitoring the spread of live marker vaccine and the gE genotype of viral field isolates.     

新疆某规模化奶牛场牛传染性鼻气管炎病毒抗体水平检测

为了调查新疆地区某规模化奶牛场牛传染性鼻气管炎（IBR）发病情况,通过采集不同生长阶段牛群血清共计362 份,使用牛传染性鼻气管炎病毒gB（IBR-gB）抗体检测试剂盒检测牛传染性鼻气管炎病毒（IBRV）抗体效价,评估该奶牛场IBRV疫苗免疫效果。结果显示,后备牛中犊牛和青年牛IBRV抗体阳性率分别为88.57%（31/35）、75.00%（21/28）;成年母牛中泌乳期母牛、干奶期母牛IBRV抗体阳性率分别为81.46%（145/178）、95.04%（115/121）。阴性数共44 份,可疑数8 份,IBRV抗体平均阳性率为88.38%;结果表明,疫苗接种后,不同生产阶段牛群均可产生不错的抗体保护效果,为奶牛场防控IBR提供依据。     

Propagation and quantitation of animal herpesviruses in eight cell culture systems

A comparative study was carried out to determine the relative sensitivities of eight different cell culture systems to six different herpesviruses of animals. The cells used were: OFL (ovine fetal lung), ML (mink lung), FK (ferret kidney), PTK-2 (potoroo kidney), TEK (turkey embryo kidney), ED (equine dermal), BT (bovine turbinate), and PK15 (porcine kidney). The viruses tested were: PRV (pseudorabies) of swine, CPHV (caprine herpesvirus), IBRV (infectious bovine rhinotracheitis virus), DN-599 strain of bovine herpesvirus type 4, EHV-1 (equine herpesvirus), and CHV (canine herpesvirus). On the basis of virus titers obtained and the time of appearance of CPE (cytopathic effects), ML cells were found to be the most useful because of their sensitivity to all six viruses tested. BT and OFL cells were also found to be highly sensitive to all viruses with the exception of CHV.     

Restriction endonuclease patterns of bovine herpesvirus type 1 isolated from bovine mammary glands

Restriction endonuclease analysis was used, in conjunction with viral neutralization and growth-curve experiments, to compare a bovine herpesvirus type 1 (BHV-1) isolate, originally obtained from bovine mammary gland lesions, with a standard BHV-1 strain, infectious bovine rhinotracheitis virus. Although differences were not detected by viral neutralization or growth-curve experiments, restriction fragment patterns generated by Bam HI, Eco RI, Hind III, and Hpa I, revealed definite differences between the isolate and the prototype strain. Additionally, Eco RI, Hind III, and Hpa I patterns revealed that the mammary gland isolate had DNA-fragment patterns characteristic of infectious pustular vulvovaginitis strain of BHV-1, type 2b. Seemingly, type-2b isolates, similar to types 1 and 2a, may be capable of causing divergent types of infection of variable severity in cattle.     

牛传染性鼻气管炎病毒gE基因的截短克隆与表达

以牛传染性鼻气管炎病毒Baaha Nu/67株的DNA作为模板，用PCR扩增gE基N并克隆至pGEM-T Easy裁体，再以此质粒作为模板将gE基因分成6个片段，分别插入原核表达载体pET32a并在大肠杆菌中进行了表达。蛋白电泳结果表明6个片段中有2个片段以可溶形式表达，1个片段以包涵体形式表达，另外3个片段没有表达。采用固定化金属离子亲和层析法在非变性条件下对两个可溶性片段进行了纯化。经免疫印迹试验，间接ELISA和交叉试验证明，两个纯化的重组蛋白均与牛传染性鼻气管炎阳性血清样品发生反应，而与牛传染性鼻气管炎阴性血清无任何反应，显示其具有良好的抗原性和特异性，可用于牛传染性鼻气管炎gE-ELISA诊断方法的建立。     

牛传染性鼻气管炎病毒LUXTM新型荧光PCR检测方法的建立

本研究针对牛传染性鼻气管炎病毒（Infectious bovine rhinotracheitis virus，IBRV）高度保守的gC基因设计单标记并具有自身荧光淬灭功能的LUX^TM引物，建立L刚新型实时荧光PCR方法用于快速检测IBRV。该方法对四株IBRV细胞培养物的检测均呈典型阳性反应，而对其它动物疱疹病毒以及健康牛组织DNA和细胞对照的检测结果为阴性，检测时间包括核酸提取仅需1h～2h。试验表明，LUX^TM荧光PCR法对IBRV细胞增殖病毒液的检测敏感性可达0．04TCID50，比病毒分离敏感性至少提高10倍；对10倍系列稀释的纯化IBRV核酸样品，L刚荧光PCR的检测敏感性比常规PCR可提高10^3倍。将病毒液添加到健康牛精液和血液样品中，该荧光PCR可检测到牛冻存精液中40TCID50牛抗凝全血、血清和临床精液中0．04TCID50的病毒，说明对临床样品的检测有效。本研究所建立的LUXTM荧光PCR方法快速敏感，适合应用于活牛及其遗传物质的进出口检疫、养牛业疾病防控等领域对IBRV的快速检测。     

牛传染性鼻气管炎病毒的分离鉴定与灭活疫苗免疫效果研究

由2例疑似牛传染性鼻气管炎（IBR）病例的荷斯坦奶牛分离到一株病毒,命名为IBRV—C1株。该病毒可被IBR标准阳性血清完全中和;接种MDBK细胞可出现IBR病毒典型细胞病变效应;选取IBR病毒gB蛋白基因序列设计引物进行PCR检测和基因测序,结果可扩增出特异性目的片段;动物回归试验显示,3头牛均可见体温升高、鼻流粘液、呼吸困难等典型的IBR临床症状。在此基础上制备了三批牛传染性鼻气管炎灭活疫苗,并进行了疫苗安全性和效力试验,结果表明三批疫苗对靶动物安全,免疫效果较好,免疫牛中和抗体效价几何平均值可达1：41以上,攻毒保护率达5／5。     

Comparison of the herpesviruses of cattle by DNA restriction endonuclease analysis and serologic analysis

Reference strains and field isolates of herpesviruses recovered from cattle in the United States were compared by restriction endonuclease (RE) analysis and the indirect fluorescent antibody test. As a result of these comparisons, 5 major biotypes of bovine herpesvirus (BHV) were defined. These types were (i) infectious bovine rhinotracheitis virus (BHV-1), (ii) bovine herpes mammillitis virus (BHV-2), (iii) malignant catarrhal fever (MCF) virus (herpesvirus alcelaphinae), (iv) the group of slow-growth isolates represented by the prototype strain Movar 33/63 (bovine cytomegalovirus candidate), and (v) the syncytia-forming Pennsylvania 47 strain. Bovine herpesvirus-1 and BHV-2 did not cross-react serologically with any other type of BHV tested. A low, but consistent level of serologic cross-reactivity was detected among MCF virus, the Movar group, and Pennsylvania 47. Several nonsyncytial, slow-growth strains, which were recovered from dissimilar clinical syndromes and were serologically related to Movar 33/63, exhibited similar DNA RE cleavage patterns, confirming their identity as members of a single type. There was no isolate from American domestic cattle similar to the African MCF virus, which has been sporadically isolated from exotic ruminants in the United States. The African MCF virus isolated during a MCF epizootic in a United States zoo exhibited some DNA RE cleavage differences in comparison with the MCF virus world prototype strain WC 11, indicating that strain diversity exists within this biotype.     

Molecular diagnosis of alcelaphine herpesvirus (malignant catarrhal fever) infections by nested amplification of viral DNA in bovine blood buffy coat specimens

A fragment of alcelaphine herpesvirus-1 (AHV-1; malignant catarrhal fever) DNA was subcloned into pUC 18 and sequenced. The subclone hybridized strongly to AHV-1 DNA, weakly to alcelaphine herpesvirus-2 (AHV-2) DNA, and not at all to DNA from bovine herpesvirus-1 (BHV-1; infectious bovine rhinotracheitis [IBR] virus), bovine herpesvirus-2 (BHV-2; bovine herpes mamillitis [BHM] virus), and bovine herpesvirus-4 (BHV-4; isolate DN599). A 2-stage (nested) polymerase chain reaction (PCR) diagnostic test was devised based on a portion of the subcloned AHV-1 DNA sequence. First and second stage amplified AHV-1 DNA targets were 487 and 172 base pairs (bp) in length, respectively. Unique Pvu II and Stu I restriction endonuclease cleavage sites confirmed the identity of amplified AHV-1 DNA. Five AHV-1 and 2 AHV-2 isolates were identically and specifically PCR positive. BHV-1, BHV-2, and BHV-4 viruses were negative by the same procedure. As little as 0.01 TCID50 AHV-1 was detected using the nested amplification procedure. Simple methods of buffy coat isolation from bovine blood were employed to prepare specimens for PCR. An AHV-1-infected calf was PCR positive from 3 to 77 days postinoculation (PI), with rising seroconversion first noted 14 days PI. The AHV-1 DNA sequence was 62% homologous to a portion of the Epstein-Barr virus genome. The nested PCR procedure may improve the viral diagnosis of clinical and subclinical alcelaphine herpesvirus infections.