狂犬病弱毒细胞苗应用后效果观察与狂犬病的综合防治

<正> 狂犬病是一种危害极大,人畜共患的急性传染病。它是由弹状病毒科、狂犬病毒属的狂犬病病毒引起的一种致死性脑脊髓炎。据世界卫生组织宣布,全世界每年被疯狗咬伤后发此病人数多达100万人以上(不包括我国),而且至今临床上仍无有效疗法。病死率     

狂犬病口服疫苗SRV9毒株基因序列的生物信息学分析

为了解狂犬病口服疫苗SRV₉毒株的基因序列与生物学特性的关系,并就其主要抗原位点与国内外现用狂犬病疫苗生产毒株进行比较,明确其作为口服疫苗株的分子基础,本试验通过RT-PCR方法对狂犬病口服疫苗SRV₉毒株的N、P、M、G、L基因分别进行克隆,并分别连接于pMD19-T载体,经酶切、测序鉴定后,用DNAStar软件对全基因序列进行分析,并与11株目前生产用狂犬病疫苗株进行基因序列比对分析和主要抗原位点的比较.狂犬病口服疫苗SRV₉毒株N、P、M、G、L基因序列与其他毒株的序列同源性为81.8%~100.0%,由全基因组进化树可知,SRV₉毒株与所有疫苗株在同一个大的分支内,均属于基因Ⅰ型,其中狂犬病口服疫苗SRV₉毒株与ERA、SAD B19、SAG-2等口服疫苗株的进化距离最近,而与疫苗生产毒株aG、RC-HL 之间的进化距离则较远.狂犬病口服疫苗SRV₉毒株与各疫苗株的糖蛋白不同结构区的氨基酸同源性分析表明,狂犬病口服疫苗SRV₉毒株与SAD B19、SAG-2、ERA口服疫苗株的膜外区、跨膜区和膜内区的同源性最高.狂犬病口服疫苗SRV₉毒株的基因组结构和抗原基因位点特征均与目前生产用口服疫苗株相似,这为今后狂犬病口服疫苗的研制和通过分子生物学技术构建基因重组弱毒疫苗株的研究提供了试验依据.     

狂犬病无毒疫苗株SRV9G基因主要功能区的序列分析

通过反转录－聚合酶链反应（ＲＴ－ＰＣＲ）扩增出了狂犬病无毒疫苗株（ＳＲＶ９）糖蛋白（Ｇ）基因膜外主要功能区的两个片段，共约７４０个ｂｐ（４５０￣１１４４），含有可以诱导中和抗体的两个抗原决定簇和决定毒力及与神经细胞受体结合部位的基因片段。通过平瑞连续将两片段克隆到ｐＵＣ１８的ＳｍａＩ位点。采用Ｓａｎｇｅｒ双脱氧终止法测定ｃＤＮＡ片段的核苷酸序列，并推导出其氨基酸序列。将这一序列与已发表的狂犬病病毒     

利用电穿孔法对狂犬病病毒SRV9 Ψ区缺失株病毒的拯救及鉴定

探讨电穿孔转染法对SRV9Ψ区缺失株重组病毒的拯救及鉴定。利用电穿孔细胞转染法,将纯化的Ψ区缺失株pcDNA-NPMG-L全长质粒和pcDNA-N、pcDNA-P、pcDNA-M、pcDNA-G和pcDNA-L辅助表达质粒共转染至BHK-21细胞中,并进行盲传,借助RT-PCR、间接免疫荧光试验、Western-blot及透射电子显微镜对重组病毒进行鉴定。结果显示,重组病毒能够产生绿色荧光,透射电子显微镜观察可见典型的弹状病毒,对重组毒株与亲本毒株G蛋白进行Western-blot验证,可获得相应目的条带。结果表明,通过电穿孔细胞转染法,能成功拯救出重组病毒SRV9Ψ区缺失株,为病毒的拯救提供新的转染方法,并能有效提高转染效率,为研发新型狂犬病疫苗提供参考。     

种猪群普免伪狂犬病弱毒活苗的效果观察

对于种猪来说，猪伪狂犬病疫苗的程序安排有两种操作方法：一个是跟胎次产前15～20天注射，一个是种猪全群普免。针对全群普免猪伪狂犬病活毒疫苗的安全性和效果，笔者在规模养猪场的动态生产中做了如下观察。     

猪伪狂犬病基因缺失弱毒疫苗的研发及应用进展

猪伪狂犬病(Pseudorabies)是一种以发热、脑脊髓炎、繁殖障碍为主要症状的急性、热性传染病.病原为伪狂犬病病毒(Pseudorabies virus,PRV).近年来该病给我国养猪业造成了重大的经济损失.目前该病尚无特效治疗药物,主要采用疫苗接种作为重点防控手段.因此,本文重点综述了近年来临床使用较广泛的猪伪狂犬基因缺失弱毒疫苗的研发及应用情况.     

狂犬病街毒的分离与鉴定

本课题组自2004年开始动物狂犬病灭活疫苗(FLury LEP株)的研制,在对疫苗进行评价的过程中,对一份来自广西的狂犬病病犬脑组织进行了鉴定,旨在为疫苗的本动物攻毒试验提供适宜的攻击毒株,并为我国狂犬病分子流行病学研究提供依据.鉴定结果如下.     

Oral immunisation of mice with a recombinant rabies virus vaccine incorporating the heat-labile enterotoxin B subunit of Escherichia coli in an attenuated Salmonella strain

To investigate effective new rabies vaccines, a fusion protein consisting of the rabies virus (RV) glycoprotein and the heat-labile enterotoxin B subunit of Escherichia coli (LTB) was successfully constructed and delivered in a live attenuated Salmonella strain LH430. Mice were immunised with LH430 carrying pVAX1-G, pVAX1-G-LTB or pVAX1-ori-G-LTB. The antibody titres of mice immunised with oral LH430 carrying pVAX1-G-LTB or pVAX1-ori-G-LTB were significantly higher than those of pVAX1-G-immunised mice. The results of the challenge with the rabies virus standard strain (CVS-11) showed that the LH430 strain carrying the G-LTB gene induced immunity and elevated IL-2 levels in immunised mice (⁷P < 0.01), whereas LH430 carrying pVAX1-G did not contribute to protection. These results show that LH430 carrying recombinant G-LTB could provide overall immunity against challenge with CVS-11 and should be considered to be a potential rabies vaccine.     

Safety and immunogenicity of a vaccine bait containing ERA strain of attenuated rabies virus.

Ninety percent of foxes fed commercial ERA vaccine in a specially designed bait developed rabies serum neutralizing antibodies. The vaccine bait did not cause clinical signs of rabies when consumed by foxes, raccoons, skunks, dogs, cats, cattle and monkeys. When presented, in the laboratory, to wild rodents of the species Microtus, Mus musculus and Peromyscus, the vaccine baits caused vaccine-induced rabies only in Mus musculus. Laboratory mice of the CD-1 and CLL strain were susceptible to vaccine-induced rabies; however, studies showed that transmission of virus to other animals did not occur. These studies suggest that the vaccine bait described could be useful in a rabies control program in areas where foxes and wild dogs are the principal vectors.     

伪狂犬病病毒弱毒株LY株的分离鉴定

从辽阳某猪场的10日龄仔猪中分离到1株病毒,经纯化后测得其毒价为107.29TCID50/mL.细胞中和试验表明,该病毒能被猪伪狂犬病病毒标准阳性血清所中和.电镜下可见到典型的疱疹病毒粒子,具有囊膜及外周纤突.所分离的病毒对氯仿、胰蛋白酶、乙醚敏感,在pH5.0～9.0下稳定,56℃ 30 min可以灭活.应用特异性引物,通过PCR能扩增出伪狂犬病病毒1 240 bp的gD基因.分离病毒对3日龄乳鼠有一定的致病力,但对家兔、3～5日龄仔猪及妊娠母猪都有很高的安全性.用不同剂量的病毒培养液肌肉注射于3～5日龄仔猪,14 d后用105.7TCID50伪狂犬病病毒强毒攻击,所有试验仔猪均可得到有效保护.用分离毒免疫母猪,其后代可获高滴度的母源抗体,15日龄的仔猪能抵抗105.7TCID50强毒的攻击.试验的结果初步说明,所分离的病毒为伪狂犬病病毒(命名为PRV LY株),并可能是一株弱毒株,而且具有很好的免疫保护作用.     

Establishment of an attenuated strain of bovine respiratory syncytial virus for live virus vaccine

To develop a live virus vaccine for the prevention of bovine respiratory syncytial (BRS) virus infection in calves, an attempt was made to produce an attenuated virus. The RS-52 strain of BRS virus, isolated from the nasal secretions of a naturally infected calf, was subjected to serial passages in adult hamster lung established (HAL) cells at 30 degrees C and the attenuated rs-52 strain as a live virus vaccine was established. The rs-52 strain multiplied better at 30 degrees C than at 34 or 37 degrees C in HAL cells. The differences in the highest virus titers of this strain between the culture temperature of 30 degrees C and that of 34 or 37 degrees C were more than 2.25 log TCID50. Colostrum-deprived newborn calves and 2 approximately 4 months old calves inoculated with the rs-52 strain manifested no abnormal clinical sings at all. However, all inoculated calves produced serum neutralization antibody. When the colostrum-deprived newborn calves immunized with the rs-52 strain were challenged with the virulent NMK7 strain of BRS virus, they exhibited no pyrexia or other abnormal clinical signs at all. An attempt was made to recover the virus from nasal secretions of these calves, but in vain. On the other hand, a nonimmunized control colostrum-deprived newborn calf developed slight fever, mild cough, and slight serous nasal discharge after challenge exposure. The virus was recovered from nasal secretions of this calf. From these results, it was considered that the rs-52 strain could be used as an attenuated live virus vaccine for prevention of BRS virus infection.     

Identification of fox rabies by a monoclonal antibody directed against nucleocapsid of a street rabies virus

Hybridomas were prepared by fusion of spleen cells from BALB/c mice immunized with dog rabies isolates from Nigeria with P3x63Ag8 myeloma cells. More than 69 hybridomas secreted antinucleocapsid (antiNC) antibodies when tested with homologous viruses by indirect immunofluorescence. One hybridoma (Z144-88) was found which secreted antiNC antibody that reacted negatively with fox rabies isolates from the Federal Republic of Germany, Switzerland and France and with rabies-related viruses and European bat isolates. It reacted positively with other strains/isolates of rabies virus. It is possible to use this antiNC monoclonal antibody (mab) for the investigation of fox rabies outbreaks in Europe.