某猪场猪瘟强毒、弱毒抗体水平的检测

应用猪瘟单克隆抗体纯化酶联免疫吸附试验方法，对河南某猪场47份母猪血清进行猪瘟抗体检测，有5份血清呈猪瘟强毒抗体阳性，阳性率为10.6%，猪瘟弱毒抗体阳性率为95.7%，其群体保护率为93％。在9份仔猪血清中，猪瘟强毒抗体为阴性，猪瘟弱毒抗体阳性率为22％，只有17％的群体保护率。检测结果表明：该猪场可能有猪瘟强毒感染。     

几种犬瘟热弱毒疫苗免疫效果比较研究

选用小熊猫(LP)株犬瘟热病毒(CDV)驯化致弱毒株为种毒研制的CD弱毒苗与另外4种CD弱毒疫苗,分别接种于5组易感幼犬,于最后1次接种后第14d和第21d采血,分离血清测定CDVSN抗体效价,并于第21d采血后用CDV强毒攻击,统计保护率。结果5组犬免疫后其中和抗体都有不同程度升高,分别从1∶10以下升高到1∶25～1∶360不等,选用LPV70毒种作为种毒的第1组犬免疫抗体效价最高,平均达到1∶185以上,攻毒试验保护率达到100%,2组抗体效价达到平均数1∶180,保护率达到90%,3组、4组抗体平均水平1∶30和1∶40,攻毒试验保护率分别只有40%和50%,5组平均抗体水平为1∶140,攻毒试验保护率为87.5%。     

猪伪狂犬病野毒感染的临床诊断、血清学调查以及控制措施

目的为某规模化猪场猪伪狂犬病病毒野毒株感染防控工作提供科学的免疫防控方案。方法对某发病猪群（采用Bartha-K61经典毒株疫苗进行了猪伪狂犬病免疫）进行流行病学调查,并采用ELISA方法检测其猪伪狂犬病gB抗体和gE抗体水平。结果根据调查、解剖和血清抗体检测结果,初步确诊该发病猪群为猪伪狂犬病野毒感染。通过采取紧急免疫伪狂犬病HB2000毒株疫苗、调整免疫程序和配合药物治疗等措施,育肥猪死亡率从2.56%降低至0.60%;除了4周龄及12周龄猪群外,其余猪群伪狂犬病野毒抗体水平全部下降;种公猪、8周龄、10周龄、14周龄猪群伪狂犬病野毒抗体阳性率均为0。结论Bartha-K61经典毒株疫苗并不能提供完全的保护力,通过紧急免疫与流行毒株同源性较高的HB2000毒株疫苗,加强生物安全管理工作,能够有效控制猪伪狂犬病野毒感染。     

不同新城疫弱毒苗对新城疫病毒强毒的免疫保护试验

用NDV的LaSota株、VG/GA 株、VH 株、PHY LMV 42株及Clone 30株弱毒疫苗免疫SPF鸡后 ,通过对雏鸡免疫后的血清抗体监测表明 ,4种弱毒疫苗激发雏鸡的抗新城疫病毒抗体滴度在 7log2水平以下 ,且差异不显著。通过以上 4种新城疫弱毒疫苗对新城疫病毒东台强毒株的免疫保护试验表明 :至少单独使用弱毒疫苗 ,不能对东台地区流行的新城疫病毒强毒株提供有效保护 ,保护率在 60 %～ 74%     

猪伪狂犬病母源抗体衰减规律及适时首免试验

试验采用伪狂犬病gB抗体ELISA试剂盒,分别检测3日龄和1、2、3、4、5、6、7、8、9、10周龄未免疫猪伪狂犬病母源抗体和相应日龄免疫后3周的伪狂犬病gB抗体,以gB抗体阳性率和S/N值分析猪伪狂犬病母源抗体衰减规律和最佳首免时间。结果表明,母猪分娩前1个月免疫伪狂犬病gE基因缺失弱毒苗,所产仔猪能获得高水平的母源抗体;随着仔猪日龄增加,抗体水平逐渐降低,能维持到10周龄。仔猪在5周龄前免疫伪狂犬病疫苗,母源抗体干扰主动免疫,5周龄后免疫抗体水平均有上升;该场仔猪伪狂犬病最佳首免时间为35~42日龄。     

猪伪狂犬病灭活疫苗(HB-J株)对兔与猪免疫攻毒保护平行关系的研究试验

用研制的连续3批猪伪狂犬病灭活疫苗(HB-J株)分别以不同剂量免疫健康兔和断奶仔猪,检测其免疫28 d后的血清抗体,采用血清中和试验法测定血清中和指数,并对免疫28 d后的兔和断奶仔猪分别进行攻毒,统计各组兔和断奶仔猪免疫后攻毒保护率。结果表明,兔免疫28 d后的血清抗体中和指数为794～1258时保护率为60%～80%,血清抗体中和指数≥1479时可获得100%保护;仔猪免疫28 d后的血清抗体中和指数为229～269时保护率为60%～80%,血清抗体中和指数≥331时可获得100%保护。兔与仔猪对猪伪狂犬病灭活疫苗(HB-J株)均产生良好的免疫应答反应,抗体值较高者获得保护率相对较高,兔与猪免疫与攻毒保护呈现平行关系。     

伪狂犬病免疫净化方案的评价

从一伪狂犬病阴性场选肉仔猪77头,均在2日龄鼻内接种伪狂犬病gE基因缺失弱毒疫苗1头份,免疫前采血,以后每间隔两周采血1次直至18周龄,检测并分析每份血样中的gE和gB抗体。另从一伪狂犬病阴性场选后备母猪50头,于77、147、175日龄肌注伪狂犬病gE基因缺失弱毒疫苗,于40、60、76、91、114、143、161、173、191、226日龄采血,检测并分析每份血样中gB抗体。结果表明,肉仔猪各周龄伪狂犬病野毒抗体(gE)均为阴性,疫苗母源抗体(gB)随日龄的增加而下降,但在114日龄有5头猪gB抗体阳转;免疫伪狂犬病gE基因缺失弱毒疫苗的后备母猪,首免后抗体上升,二免后抗体明显上升、并保持高水平,第3次免疫后抗体较二免后上升不明显。     

狂犬病灭活疫苗PV2061株的免疫原性试验

本试验对兽用狂犬病灭活疫苗PV2061株的保护效率进行评估,分别以常量、1/2剂量和1/4剂量免疫本动物并进行街毒攻击试验。血清中和抗体检测结果表明,前2组在免疫4周后抗体阳性率均为100%,抗体的平均滴度分别为4.86 IU/mL和1.18 IU/mL,1/4剂量组的抗体滴度较低,平均滴度仅为0.36 IU/mL。攻毒后前2组的保护率为100%,1/4剂量组的保护率为40%,阴性对照组攻毒后全部死亡。对试验犬的脑组织进行直接荧光抗体染色检测表明仅有死亡犬脑组织中有狂犬病病原存在。综上所述,狂犬病灭活疫苗PV2061株正常免疫剂量和1/2免疫剂量的强毒攻击保护率均在80%以上,阴性对照犬的死亡率高于80%,符合国际标准。本试验为灭活疫苗PV2061株的保护效率提供了试验依据,为其实际应用并投入生产奠定了试验基础。     

豚鼠对猪细小病毒弱毒苗抗体反应的研究(摘要)

用不同批次、不同剂量、不同保存时间的猪细小病毒Ｎ株弱毒苗接种豚鼠 ,观察豚鼠对ＰＰＶＮ株弱毒苗的抗体反应。其结果如下 :用 4种不同剂量的ＰＰＶＮ株弱毒苗免疫豚鼠 ,免疫后 14天均产生抗体反应 ,ＰＰＶＨＩ价分别为 :0 1ｍｌ剂量为 1:16～ 1:6 4;0 2ｍｌ为1:8～ 1:32 ;0 5ｍｌ为 1:16～ 1:32 ;1 0ｍｌ为 1:16～ 1:6 4,而对照豚鼠抗体反应为阴性 ,可见仅需 0 1ｍｌＰＰＶＮ株弱毒苗便可引起豚鼠产生抗体反应。同时比较了不同批次的ＰＰＶＮ株弱毒苗接种豚鼠产生抗体反应的情况 ;3批ＰＰＶＮ株弱毒苗接种豚鼠后 14天全部出现抗体反…     

鸡病毒性关节炎弱毒苗的研制 Ⅱ.弱毒株的免疫原性

应用具有良好安全性的鸡病毒性关节炎病毒（AVAV）弱毒JN-1株免疫1日龄肉鸡40只,分别用琼脂扩散试验、间接ELISA和中和试验（NT）检测免疫鸡血清中的AVAV抗体。中和抗体于免疫后7d开始出现,14d后全部阳转;ELISA抗体也于免疫后7d开始显示阳性,21d后全部阳转;琼脂扩散抗体于免疫后14d开始阳转,28d以后全部显示阳性。分别在免疫后7、14、21和 28d于足掌皮下用强毒攻击免疫鸡,临床保护率分别为2/10、9/10、10/ 10、10/10,病理保护率分别为0/10、7/10、9/10、10/10。体外抗病毒谱试验显示,弱毒株的免疫血清能中和AVAV J-1株、S_(1133)株、FDO株和H_(9307)株。上述实验结果表明,AVAV弱毒株具有良好的免疫原性。     

狂犬病病毒入胞途径的初步探索

狂犬病病毒(rabies virus,RABV)具有高度嗜神经性,通过识别细胞膜上特异性受体并借助内吞途径侵入细胞。为了探究其入胞途径,本研究在人神经瘤细胞(SH-SY5Y)和非洲绿猴肾上皮细胞(Vero)上,应用氯丙嗪(chlorpromazine)、制霉菌素(nystatin)、巴弗洛霉素a1(bafilomycin a1)、dynasore等抑制剂处理细胞后,进行RABV感染,通过检测病毒N基因拷贝数和RABV效价,对RABV入胞途径进行初步探究。结果显示,RABV通过网格蛋白介导、低pH值和发动蛋白(dynamin)依赖途径侵入SH-SY5Y和Vero细胞,但不通过小窝蛋白依赖途径入胞。这些结果为进一步研究狂犬病病毒感染机制和药物靶点研究提供了新的数据。     

Cellular response to rabies virus infection

The effects of rabies virus on host cells were studied and compared to those obtained with another rhabdovirus, vesicular stomatitis virus [J. Virol. 34, 777-781 (1980)]. We show here: (1) that rabies infection has no effect on cell morphology, while infection with vesicular stomatitis virus caused cell retraction. Thus, only vesicular stomatitis virus induced a depolymerization of the microfilaments; and (2) that microtubules and microfilaments do not play a major role in rabies virus production, as it is suggested by results obtained with several effectors (colcemid, colchicine and cytochalasin-B) which directly or indirectly affect cytoskeleton organization. The same properties were observed with directly or indirectly affect cytoskeleton organization. The same properties were observed with vesicular stomatitis virus. Furthermore, the use of cytochalasin-B shows that an inhibition of glycosylation of the virion spike protein occurs only in rabies infected cells. As vesicular stomatitis viral glycosylation is normal in cytochalasin-B treated cells, results obtained indicate that two types of interactions can occur between a virion and the host-cell depending on the rhabdovirus type.     

Survival of rabies virus under external conditions

The survival of the street rabies virus in a 10% suspension, prepared from the salivary gland of a naturally infected fox, was studied under various conditions. A bioassay and titration on mice were used for the identification of the virus in different intervals. The heat inactivation of the virus in a suspension kept in a test tube at the temperatures of 20 degrees C and 37 degrees C was performed in two stages. The rapid reduction of the titre within 24 hours was followed by a slower decrease, reaching total inactivation after 96 hours at both temperatures. When the virus was tested by means of the contamination of various substrates (glass, metal sheet, plant leaf) with 0.1 ml of infection suspension in a thin layer, the longest survival of the virus was recorded at the temperature of 5 degrees C--144 hours. At the temperature of 20 to 21 degrees C the virus kept its activity on the glass and plant leaf for 24 hours and on the metal sheet for 48 hours although the applied drops looked like having dried. The temperature of 30 degrees C combined with intensive sunshine devitalized the virus within 1.5 hours, whereas without sunshine the virus still remained active, at the temperature of 30 degrees C, after 20 hours.     

Molecular characterization of Korean rabies virus isolates

The nucleoprotein (N) and glycoprotein (G) of 11 Korean rabies virus (RABV) isolates collected from animals diagnosed with rabies between 2008 and 2009 were subjected to molecular and phylogenetic analyses. Six isolates originated from domestic animals (cattle and dogs) and five were obtained from wild free-ranging raccoon dogs. The similarities in the nucleotide sequences of the N gene among all Korean isolates ranged from 98.1 to 99.8%, while those of the G gene ranged from 97.9 to 99.3%. Based on the nucleotide analysis of the N and G genes, the Korean RABV isolates were confirmed as genotype I of Lyssavirus and classified into four distinct subgroups with high similarity. Phylogenetic analysis showed that the Korean isolates were most closely related to the non-Korean NeiMeng1025B and 857r strains, which were isolated from rabid raccoon dogs in Eastern China and Russia, respectively. These findings suggest that the Korean RABV isolates originated from a rabid raccoon dog in Northeastern Asia. Genetic analysis of the Korean RABV isolates revealed no substitutions at several antigenic sites, indicating that the isolates circulating in Korea may be pathogenic in several hosts.     

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.     

Increased mortality in mice infected with rabies virus and subsequently vaccinated against rabies

When mice infected 1 or 2 days before by an IM inoculation after high passage of the virus in the species ("challenge virus standard" strain) received an injection of live (Flury) or inactivated virus, their mortality was increased in comparison with unvaccinated controls. In the case of the inactivated virus vaccine, mortality was proportional to the dose of vaccine received. Conversely, when vaccination was carried out in mice recently infected with the same doses of a heterologous strain adapted to foxes, this phenomenon could not be demonstrated. The consequences of these observations on failures of treatment in animals infected with a homologous strain, cases of rabies occurring after vaccination or quality control of vaccines are discussed.