中国禽(番鸭)呼肠孤病毒分离株S1基因全序列分析

采用RT-PCR技术,分别以DRV-YH、DRV-YJL两株中国禽(番鸭)呼肠孤病毒RNA为模板,扩增了S1全基因的cDNA片段.将S1 cDNA克隆到T载体后进行序列测定,测序结果表明所扩增的cDNA片段长1643个核苷酸,包含了完整的S1基因的三个开放阅读框架(ORF1,ORF2和ORF3)和基因两端的非编码区.核苷酸序列比较分析结果表明:DRV-YH与ARV-S1133,176分别有6个,10个核苷酸的差异,DRV-YJL与ARV-S1133,176分别有8个,12个核苷酸的差异,DRV-YH与DRV-YJL有4个核苷酸的差异.     

3种禽类呼肠孤病毒血清学相关性及致细胞病变差异分析

本研究旨在研究3种不同疾病型禽类呼肠孤病毒间的抗原性关系及病毒的培养特性。作者通过血清中和试验测定了禽呼肠孤病毒(ARV S1133株)、番鸭呼肠孤病毒(MDRV 9710株)、新型鸭呼肠孤病毒(NDRV NP01株)3种禽类呼肠孤病毒的血清学相关性,统计抗原相关性R值;并应用部分禽胚原代细胞及哺乳动物传代细胞对这3种病毒的培养特性进行了初步研究。结果表明,3种病毒株之间的R值很小,抗原相关性较低;三者具有广泛的细胞亲嗜性,能在多种细胞中增殖,并产生细胞病变,但病毒致细胞病变特征有所差异,ARV和NDRV均以巨融合为主,而MDRV则以细胞圆缩坏死为主。上述结果表明导致禽类不同疾病的ARV、MDRV和NDRV三者之间的抗原相关性较低,病毒的细胞培养特性也不同,细胞病变类型的差别提供了一种初步鉴别禽类呼肠孤病毒的方法。     

一步法RT-PCR检测禽呼肠孤病毒的研究

根据已发表的禽呼肠孤病毒（ARV）S1133株S1基因序列，设计合成了一对扩增跨幅为532bp的引物。这对引物对ARV标准株，分离株以及人工感染SPF鸡跗关节组织抽提的核酸进行一步法RT-PCR扩增，即将反转录和PCR反应在一个PCR反应管中一次性完成。结果该方法对ARV4个标准株和5个分离株的扩增均获得了与预期大小一致的RT-PCR产物，而对照样品的扩增全为阴性；该方法最低可检测到0.16ng的ARV RNA，还可以直接从感染鸡关节组织抽提的核酸中检测到ARV RNA，表明该一步法RT-PCR对于ARV的检测是可行的。     

禽呼肠孤病毒C-98分离株L1基因的克隆与序列分析

参考禽呼肠孤病毒S1133株（GenBank）L1基因序列设计3对特异性引物,采用RT-PCR方法对禽呼肠孤病毒内蒙古分离株C-98的L1基因进行了克隆和序列测定。结果表明：获得的C-98 L1基因全长3959 bp,其中包括21 bp的5’非编码区和56 bp的3’非编码区,阅读框位于5’端第22位核苷酸与3’端第3903位核苷酸之间。将C-98株与国内外禽呼肠孤病毒群和哺乳动物呼肠孤病毒群的不同分离株进行序列比较,结果显示：C-98与台湾地区分离株919和美国分离株1733、2408、S1133亲缘关系最近,其核苷酸同源性分别为99.8%、99.7%、99.7%、99.4%;与哺乳动物呼肠孤病毒L3基因核苷酸及其编码的氨基酸同源性较低,为43%～45%。     

用反转录聚合酶链反应检测禽呼肠孤病毒的研究

本文报告了建立反转录聚合酶链反应（ Ｒ Ｔ Ｐ Ｃ Ｒ）检测禽呼肠孤病毒（ Ａ Ｒ Ｖ）的方法,根据禽呼肠孤病毒 Ｓ１１３３ 毒株 Ｓ１ 基因序列,设计合成两对引物,用 Ｒ Ｔ Ｐ Ｃ Ｒ 技术对 ６ 株禽呼肠孤病毒国际标准株进进行了检测。结果两对引物对 ６ 株 Ａ Ｒ Ｖ 均可扩增出与预期大小相符 ５３２ｂｐ 和 ４３５ｂｐ 的 Ｒ Ｔ Ｐ Ｃ Ｒ 产物,而对其它 ６ 种禽病病原核酸的扩增结果均为阴性;该 Ｒ Ｔ Ｐ Ｃ Ｒ 可以检测出 １ｐｇ 的 Ａ Ｒ Ｖ Ｒ Ｎ Ａ 模板。     

Development of an attenuated apathogenic reovirus vaccine against viral arthritis/tenosynovitis

A fully attenuated apathogenic reovirus vaccine was developed by 235 serial passages of S1133 strain avian reovirus in embryonating chicken eggs and 100 additional passages in chicken embryo fibroblast (CEF) cultures, 65 of which were cultured at 32 C. Chickens with and without maternal antibodies to avian reovirus were vaccinated subcutaneously at 1 day of age and challenged via footpad at 14 days of age. It appeared that the 40th, 66th, and 100th CEF passage levels were apathogenic at doses ranging from 10(2.5) to 10(6.8) TCID50/chick. No gross or microscopic lesions of tenosynovitis developed in vaccinated chicks. Vaccinated chicks were protected against challenge; unvaccinated control chickens were not.     

Serologic comparison of avian reovirus isolates using virus neutralization and an enzyme-linked immunosorbent assay

The serologic relatedness of six avian reovirus isolates (CO8, S1133, 81-5, 2408, 1733, and UMI 203) were determined using a virus-neutralization (VN) test and an enzyme-linked immunosorbent assay (ELISA). Six groups of 20 specific-pathogen-free broilers each were twice infected with one of the six isolates per group. Serum was reacted against each isolate in a beta VN test in chicken embryo kidney cells and against the S1133 virus in ELISA. Relatedness (R) values, determined by cross VN, revealed that all belonged to a single serotype. However, the CO8 isolate represented a major subtype difference compared with the other isolates. R values among the five other isolates indicated minor or no subtype differences. ELISA also showed major differences between the CO8 and the other isolates.     

应用半套式聚合酶链反应检测禽呼肠孤病毒S1基因的研究

根据离呼肠孤病毒S1133毒株S1基因序列，设计合成XZ11、XZ12和XZ11、XZ33两对引物，用半套式PCR对6株禽呼肠孤病毒标准毒株的核酸进行了检测。结果6株ARV均可扩增出和预期大小相符392bp的PCR产物，而对其他6种禽病病原核酸的扩增结果均为阴性；该半套式PCR比RT-PCR更加敏感，这种方法可以检测出Ifg的ARV RNA模板。     

应用RT-PCR技术检测番鸭呼肠孤病毒

参考 Gen Bank中番鸭呼肠孤病毒 (m uscovy duck reovirus,MDRV ) S1基因序列 ,用计算机设计并合成了 1对引物 HP11、HP12 ,以此引物用 RT- PCR对番鸭呼肠孤病毒 S1基因进行了特异性扩增。结果表明 :引物 HP11、HP12能从所有供试的 4株分离毒 MDRV- MW9710、MW980 6、MW980 9、MW9810扩增出 30 0 bp S1基因 c DNA片段 ,而不能从禽呼肠孤病毒 (ARV) S1133株和番鸭胚成纤维 (MDEF)细胞培养物中扩增出任何片段 ;该 RT- PCR的检测灵敏度为 1pg的病毒核酸 ,特异性强 ,重复性好 ,对含毒细胞培养液和尿囊液只需用氯仿进行简单处理 ,即能检测出 MDRV核酸。因此认为 ,该 RT- PCR可以用于番鸭呼肠孤病毒的快速检测     

Yeast-derived sigma C protein-induced immunity against avian reovirus

Avian reoviruses (ARVs) can result in disease and economic losses in the poultry industry. Vaccines against ARV may not provide full protection and can cause adverse reactions. The coding sequence of the sigma C protein from strain S1133 of avian reovirus was expressed in Schizasaccharomyces pombe. Sigma C protein expression was demonstrated by Western blotting, and the protein was evaluated for its ability to protect specific-pathogen-free (SPF) chickens against challenge with the virulent S1133 strain. Serologic and challenge-infection data showed the efficacy of the recombinant vaccine administered orally each week for 3 consecutive wk. Sigma C protein induced antibody, as determined by enzyme-linked immunosorbent assay. Percentage (%) protection induced by the low dose (125 microg purified yeast-expressed sigma C protein/chicken) or the high dose (250 microg purified yeast-expressed sigma C protein/chicken) was 64 and 91, respectively. The commercial vaccine administered once or twice provided 82% protection. Results supported the feasibility of a plant-derived vaccine for use in poultry immunization schemes.     

Antigenic comparisons of selected avian reoviruses by use of the plaque-reduction neutralization assay

The antigenic interrelatedness of 3 clone-purified turkey reoviruses (NG-Turkey, 82-88, and NC-TEV) to each other and to 4 clone-purified chicken reoviruses (S1133, Co8, Fahey-Crawley, and avian type 2) was determined in reciprocal cross-neutralization tests, using polyclonal antisera and the plaque-reduction technique. The morphologic features of plaques formed under agar were studied for all 7 reoviruses, and size comparisons for turkey vs chicken isolates were made. All 3 turkey reoviruses (with the exception of NG-Turkey vs Fahey-Crawley chicken reovirus) formed plaques significantly (P less than 0.05) smaller than plaques produced by their chicken counterparts. The 3 turkey reoviruses were closely related to each other and to chicken reovirus CO8. The antigenic differences between turkey reoviruses 82-88 and NC-TEV and chicken reovirus S1133 were slight (minor subtype); however, the latter and NG-Turkey were serotypically distinct. The NG-Turkey and 82-88 turkey reoviruses were more related (minor subtype) to the Fahey-Crawley and avian type 2 chicken reoviruses, than was NC-TEV turkey reovirus (major subtype).     

禽呼肠孤病毒σA基因酵母双杂交诱饵载体的构建与鉴定

为了筛选与禽呼孤病毒σA基因相互作用的宿主蛋白,本试验应用酵母双杂交技术构建禽呼孤病毒σA基因的诱饵载体pGBKT7-σA。从禽呼肠孤病毒S1133标准毒株抽提RNA,采用RT-PCR方法扩增得到σA基因片段,将其连接到诱饵载体pGBKT7上,把通过测序的重组诱饵载体命名为pGBKT7-σA。将重组诱饵载体转化酿酒酵母Y2HGold后,把不同浓度的诱饵载体转化液涂布在营养缺陷型培养基上,观察该重组诱饵载体在酵母细胞中有无毒性作用和自激活现象。结果显示,酵母双杂交诱饵载体pGBKT7-σA构建成功,且对酿酒酵母无毒性和自激活现象。本研究为进一步利用酵母双杂交技术筛选与σA蛋白互作的宿主蛋白奠定了基础。     

Monitoring the Immune Status of Broilers Against Reoviruses Using Challenge and Serologic Data

Reoviruses are an important cause of suboptimum performance in commercial broilers worldwide. Integrators use the enzyme-linked immunosorbent assay against the S1133 antigen for monitoring serum of breeders for indicating pullet vaccine success. However, without correlating serology to reovirus challenge, it is difficult to determine whether titers reflect protective immunity. We developed a broiler challenge test against 2 common reovirus isolates (2408 and S1133) to evaluate the efficacy of reovirus pullet vaccine programs. Two reovirus serologic and challenge studies were undertaken using chicks from broiler integrators from the southeastern United States. Breeder flocks, from which the chicks were obtained, received at least 1 live and 2 inactivated reovirus vaccines during their pullet phase. One-day-old progeny were collected from 6 breeder flocks. At 1 d of age, 20 chicks from each broiler flock were bled, and serum was analyzed for antibodies. At 3 to 4 d of age, 20 progeny per flock were challenged with the 2408 reovirus by intratracheal route. At 10 to 14 d of age, another 20 birds per flock were challenged with the S1133 reovirus by footpad. Twenty birds per flock were used as nonchallenged controls. At 3 wk of age, all birds were killed and weighed. Percentage of protection was calculated for each flock based on the absence of gross lesions. Flocks with at least 50% protection were considered well protected. Most flocks were well protected against both viruses. The percentage of protection correlated with day-old enzyme-linked immunosorbent assay titers. Chicks from younger hens had higher titers and the best protection against challenge. Producers, whose hen flocks were monitored herein, were doing a good job of immunizing pullets against reovirus. They are now using reovirus progeny challenge studies along with breeder antibody titers to determine vaccination success of their pullets.     

番鸭呼肠孤病毒非结构基因的克隆和序列分析

参考GenBank禽呼肠孤病毒(Avian Reovirus,ARV)和番鸭呼肠孤病毒(Muscovy Duck Reovirus,MDRV)非结构基因(NS)序列设计合成一对引物,对番鸭呼肠孤病毒S14和C4株NS基因进行RT-PCR扩增,克隆到pMD18-T载体中,并对克隆产物进行酶切鉴定和测序;番鸭呼肠孤病毒NS基因由1 291 bp核苷酸组成,与禽呼肠孤病毒NS基因相比,在非编码区第1155位少一个碱基,本文第一次证实1291bp是番鸭呼肠孤病毒NS基因特有的长度;番鸭呼肠孤病毒S14和C4株NS基因的5'末端和3'末端分别为5‘GCTTTT和TCATC-3',是禽类呼肠孤病毒基因末端特有的碱基序列,S14和C4株NS基因的的有效阅读框(24～1127bp)编码367个氨基酸组成的蛋白,分子量约为40kDa;番鸭呼肠孤病毒S14和C4株NS蛋白等电点分别是7.3和7.0,GC含量分别为54.26%和53.71%,番鸭呼肠孤病毒S14和C4株NS基因间核苷酸同源性为99.3%,仅有4个氨基酸差异,S14和C4与法国番鸭呼肠孤病毒89026株NS基因核苷酸同源性分别为87.8%和87.9%,与鸡关节炎病毒S1133 NS基因同源性分别为79.0%和79.3%;进化树分析表明本研究中的两株番鸭呼肠孤病毒非结构基因(NS)与番鸭呼肠孤病毒的亲缘关系比禽呼肠孤病毒近的多,建议番鸭呼肠孤病毒应归属为正呼肠孤病毒属第二个亚群中不同于禽和内尔森贝海湾呼肠病毒独立基因群.     

Association of avian reovirus M and S genes with viral behavior in vivo. II. Viral pathogenicity

A group of avian reoviruses comprising serially passaged S1133 strains and their vaccine derivatives was examined biochemically to study the temporal evolution of the viruses and biologically to assess their relative pathogenicities. The strains fell into three groups of differing virulence, the viruses becoming less pathogenic the longer they were passaged. Protein and RNA profiles of the strains showed no distinct patterns of evolution nor any trend that could be correlated with pathogenicity. Nucleic acid hybridization studies of the strains indicated that all the genes were altered to some extent during passage. The S1 and M3 genes appeared to change the most during the first half of passage history, but later, as the virus was cold-adapted or passaged extensively, the M2, S2, and S3 genes also appeared to vary. When viruses were grouped according to virulence, the greatest changes were seen in the S1, M2, and M3 genes, suggesting that these may be associated with the virulence of a given avian reovirus strain.     

The influence of reovirus sigma C protein diversity on vaccination efficiency

Avian reovirus (ARV) is a disease agent that causes economic losses in the poultry industry. The available vaccines do not confer full protection. One possible reason is the existence in the field of many virulent serotypes with no cross protection. Several ARV strains have been isolated in Israel in the last few years. In this study, we investigated the diversity of the sigma C protein of ARV because this is the most variable protein in the virus and it induces the production of neutralizing antibodies. Sigma C from two virulent isolates was sequenced, cloned, and expressed. The protein sequence differed from the attenuated vaccine strain (strain 1133) but was similar to a U.S. virulent strain (strain 1733). Those differences led to a change in the antigenic index of the protein, mainly at three sites. Sera of infected birds in a field trial and of birds in a controlled experiment vaccinated with the recombinant sigma C protein showed high titers in enzyme-linked immunosorbent assay to the recombinant protein and lower titers to the attenuated vaccine strain. This means that sigma C can be used as a diagnostic tool for the detection of antibodies relevant for protection and in the future as a subunit vaccine. The results of this study highlight the need to reconsider vaccinations against ARV in terms of the strains to be used and of the method of identifying protective antibodies transferred to progeny.     

Coarse-spray immunization of one-day-old broilers against enteric reovirus infections.

Coarse-spray (CS) administration of a commercial S1133 reovirus vaccine was evaluated in 1-day-old specific-pathogen-free broilers for prevention of clinical infection induced by intratracheal challenge with two enteric reovirus isolates. In Expt. 1, chickens were challenged at 4 days of age with either the 2408 or CO8 isolate. In Expt. 2, chickens were challenged at 7 days of age with either isolate. In Expt. 3, chickens were challenged at 3, 5, or 7 days of age with the 2408 isolate. In Expt. 1, vaccinated birds showed significant protection against challenge with either isolate at 4 days of age as measured by morbidity, mortality, gross lesions, and body weight. In Expt. 2, vaccinated birds showed greater protection against challenge at 7 days of age. In Expt. 3, resistance in vaccinated birds increased with time between vaccination and challenge. Vaccinated birds challenged at 3 days of age showed no significant protection, whereas vaccinated birds challenged at 5 or 7 days of age had increased resistance. This vaccine did not induce a drop in weight gain, morbidity, mortality, or microscopic lesions in the tendons.     

Association of avian reovirus M and S genes with viral behavior in vivo. I. Viral persistence

Persistent infections were initiated in chickens with four different avian reovirus strains of varying virulence. Chickens 1 day old, 1 week old, or 2 weeks old were inoculated with each. Eight weeks later, isolates from all four parent strains were obtained; all isolates but one were from the tendons, and that was from the pancreas. Biochemical characterization of the isolates showed their genomes to be similar to those of the parent strains, although the proteins of the persistent isolates occasionally appeared to migrate differently from those of the original strains. Hybridization studies of the genes of the isolates indicated that at least two genes, S2 and S4, consistently seemed to undergo the greatest degree of mutation in the most virulent strain. These data suggest that the S2 and S4 genes may be associated with initiation and maintenance of persistent infection in vivo, and that changes in these genes may be noted by 56 days postinfection.     

Avian Reovirus Induces an Inhibitory Effect on Lymphoproliferation in Chickens

The cellular immune responses of chickens inoculated with the vaccine strain S-1133 and/or a field isolate VA-1 of avian reovirus (ARV) were studied. Both strains of virus caused inhibition of the phytohaemagglutinin (PHA)-induced lymphoproliferative response of peripheral blood mononuclear cells (PBMC) and splenic mononuclear cells (SMC) during the initial stage from day 4 up to day 10 post-inoculation (PI), with a later return to the normal value. The inhibition in the PHA-induced lymphoproliferation of SMC could be partially overcome by depletion of adherent cells. The supernatant of the PHA-stimulated SMC culture was also checked in vitro for the presence of suppressive factor(s) produced in response to ARV infection. The culture supernatant from chickens at day 5 PI caused significant inhibition of the PHA-induced lymphoproliferation of control birds, suggesting the presence of suppressive factor(s). ARV infection also significantly inhibited IL-2 production on day 5. There was a significant increase in nitric oxide production by the splenic mononuclear cells of chickens inoculated with either strain of ARV.     

Onset of progeny immunity against viral arthritis/tenosynovitis after experimental vaccination of parent breeder chickens and cross-immunity against six reovirus isolates

Immunization of breeder chickens by eyedrop with viral arthritis/tenosynovitis vaccine strain S1133 (73rd egg passage) gave no immunity against day-old oral challenge of their progeny at 1 week postvaccination of the breeders, but progeny immunity was observed at 3, 4, 5, 6, and 7 weeks postvaccination of the breeders. Oral cross-challenge of immune progeny with viral isolates from Connecticut, West Virginia, California, Indiana, Pennsylvania, and Minnesota showed that in vitro neutralization of an isolate by anti-S1133 antiserum correlated with in vivo immunity of the progeny against oral day-old challenge with such an isolate.