伪狂犬病基因缺失疫苗株(SA215)生物学特性研究

测定了伪狂犬病gE^-／gI^-／TK^-／LacZ^ 基因缺失疫苗株(SA215)的致细胞病变效应、安全性、免疫原性和接种动物抗体消长规律等生物学特性。试验结果显示，该疫苗株能在Vero细胞上适应生长，并形成典型的蚀斑。其对1日龄仔猪、妊娠母猪、牛、羊以及家兔安全，无不良接种反应，接种动物不向外散毒。SA215疫苗接种猪能抵御高剂量(10’PFU)Fa株强毒感染，攻毒后试验猪的发热期、增重受阻天数、散毒滴度略低于Bartha株疫苗接种猪，低于对照组猪。SA215接种猪能维持长时间的高水平中和抗体滴度。试验结果表明，SA215株是一株安全、免疫原性好的疫苗株。     

牛O型A型口蹄疫双价灭活疫苗研究：A型毒种的选择

收集保藏的６株口蹄疫Ａ型牛源强毒，适应乳鼠５代，转适ＢＨＫ－２１细胞单层１０代，用弗氏安全佐剂制成疫苗免疫豚鼠。综合分析其对实验动物及制苗细胞的适应性，病毒感染性滴度、豚鼠抗强毒攻击的免疫原性、血清中和抗体应答的抗原广谱性表明，在６株毒中ＡＦ／７２具有更好的适应性，病毒滴度高，免疫原性好，抗原谱广。     

猪乙型脑炎(HW1株)细胞灭活疫苗免疫抗体水平分析

为评估猪乙型脑炎(HW1株)细胞灭活疫苗的免疫原性,用商品化的乙型脑炎鼠脑疫苗、乙型脑炎弱毒疫苗(SA14-14-2株)以及自制乙型脑炎细胞灭活疫苗(HW1株)分别免疫仔猪,通过抗体水平监测试验、中和抗体试验、小鼠攻毒保护试验分别检测了其特异性抗体消长情况、中和抗体效价产生情况及疫苗对小鼠的攻毒保护率。结果显示,3种疫苗均能产生中和抗体,乙型脑炎细胞灭活疫苗免疫组中和抗体水平要高于鼠脑疫苗和弱毒疫苗免疫组,乙型脑炎细胞灭活疫苗和弱毒疫苗免疫组对小鼠的攻毒保护率高于鼠脑疫苗免疫组,但两者之间差异不显著。抗体消长情况显示,至8周观测期结束,鼠脑疫苗免疫组的抗体阳性率为80%,乙型脑炎细胞灭活疫苗和弱毒疫苗免疫组抗体阳性率为100%。结果表明猪乙型脑炎(HW1株)细胞灭活疫苗的免疫原性优于鼠脑灭活疫苗和弱毒疫苗。     

应用血凝抑制试验鉴别伪狂犬病病毒感染猪和疫苗接种猪

血凝抑制试验可用于鉴别伪狂犬病强毒感染猪和糖蛋白ｇⅢ缺失菌免疫接种猪，疫苗株ｄｌｇ９２／ｄｌｔｋ无凝集鼠红细胞的活性，ｄｌｇ９２／ｄｌｔｋ疫苗株接种５次的猪不产生ＨＩ抗体，但能产生抗伪狂犬病病毒）效价为１２８－５１２）的中和抗体。而这些猪在接种强毒后１－２周能产生ＨＩ抗体，因此，ＨＩ试验能鉴别感别感染强毒株的猪与用ｇⅢ缺失苗免疫的猪。     

雏鸡接种传染性喉气管炎病毒细胞结合弱毒疫苗的免疫应答…

用细胞结合疫苗（ＣＡ）接种的雏鸡对传染性喉气管炎（ＩＬＴ）可获得很高的免疫保护力，用ＣＡ疫苗或无细胞（ＣＦ）疫苗接种的雏鸡，可分别在血清中检出病毒中和抗体及ＩｇＧ和ＩｇＭＥＬＩＳＡ抗体。但在接苗雏鸡的气管冲洗液中未检出抗体，接种ＣＡ疫苗的银鸡比接种ＣＦ疫苗的雏鸡能产生更明显的抗体应答，抗体效价与ＩＬＴ强毒攻击产生的保护不呈正相关，皮下接种ＣＡ苗或ＣＦ苗后，可于接种后１～６天从肝，脾，胸腺，肺或其它     

鸡支原体,鸡传染性鼻炎双价二联油乳剂灭活疫苗的研究

应用鸡败血支原体国际标准株（ＭＧＲ）和鸡副嗜血杆菌（ＨＰＧ）国际标准株Ａ型（ＨＰＧ２２１）和Ｃ型（ＨＰＧ６６８）制备了抗鸡支原体病（ＡＭ）和鸡传染性鼻炎（ＩＣ）的双价二联油乳剂灭活疫苗。通过多批次ＳＰＦ鸡免疫试验,进行了疫苗安全性、抗体产生时间及抗体动态变化规律、攻毒保护率、免疫期及现地鸡群的中间试验。结果表明,疫苗接种后１０～１５天可相继产生ＭＧ和ＨＰＧ血清抗体;接种６个月内,强毒攻击的免疫保护率为９１％～１００％;各项试验的指标不低于各自的单苗,具有很好的推广应用价值。     

口服狂犬病疫苗（SAG—2）对犬的免疫原性,效力和安全性

研究了ＳＡＧ－２致弱狂犬病病毒疫苗对实验小猎兔犬的免疫原性和效力。试验共分四线，每组１０只犬，分别在舌上口服接种ＳＡＧ－２１ｍｌ／只或在诱饵只在１．５ｍｌ／只，接种后１８０天，所有的犬用狂犬病毒攻击，测定各组的抗体应答，结果，疫苗直接加到舌上经用诱饵接种法效价高。但各组间差异无统计学意义，所有免疫犬都存活，而８０％对照犬死亡，证明ＳＡＧ－２经口免疫犬是安全有效的。     

猪细小病毒四川毒株的免疫原性研究

用兔和猪两种动物模型结合猪的繁殖性能生产指标综合主人了猪细小病毒（ＰＰＶ）四川毒株ＳＲ－１、ＳＲ－２和ＳＲ－３的免疫原性。试验结果表明，ＰＰＶ ＳＲ－１和ＳＲ－３免疫兔和猪后期抗体效介上升最快，下降也较为缓慢；免疫母猪窝总产仔数高，不出现死产和干尸化现象，窝分散率为０；ＳＲ－２株在仔猪原代肾细胞上的产毒量较高，可以作为疫苗毒株。     

禽脑脊髓炎油佐剂灭活疫苗免疫效果观察

将感染了ＡＥＶ－ＶａｎＲｏｃｋｅｌ株的ＳＰＦ全胚磨制的乳剂离心分离,取上清液制成抗原含量不同的两种灭活疫苗。将两种疫苗各接种３月龄的ＳＰＦ鸡,未见接种鸡出现症状。４周后以强毒ＡＥＶ攻击,所有疫苗接种鸡皆被保护,组织学检查进一步证明了疫苗的效力。抗原含量较高的疫苗引起的保护力更好,作者认为攻击时经过脑内接种更适合于临床评价疫苗效力。     

猪细小病毒病弱毒疫苗免疫效力评价及临床免疫试验

为制定猪细小病毒病弱毒疫苗效力检验的标准,用3批猪细小病毒病弱毒疫苗进行接种猪与接种豚鼠的平行试验;同时进行临床免疫试验。3批疫苗接种豚鼠和猪后定期进行PPVHI抗体检测;猪于免疫后攻毒,并进行病毒分离。免疫母猪在怀孕早期进行强毒攻击,40d扑杀进行病毒分离。用3批疫苗免疫后备母猪统计产仔成绩。结果显示,豚鼠接种后21d、猪接种后7d全部产生抗体反应。免疫攻毒的猪均未从血浆和内脏中分离到病毒,而从对照猪分离到病毒;怀孕母猪强毒攻击后扑杀,胎儿病毒分离均为阴性,而对照猪胎儿病毒分离为阳性;统计数据表明免疫猪的产仔成绩比未免疫猪高,平均每窝多产活仔1.85头,少产死胎木乃伊胎0.65头。结果表明,当免疫豚鼠PPV HI≥64时,免疫猪能抵抗PPV强毒攻击,两者呈正相关;免疫母猪的攻毒试验表明免疫母猪能抵抗PPV经胎盘感染;临床免疫试验证明疫苗具有良好的免疫原性和安全性。     

Efficacy of a pseudorabies virus vaccine based on deletion mutant strain 783 that does not express thymidine kinase and glycoprotein I.

The vaccine efficacy of a genetically engineered deletion mutant strain of pseudorabies virus, strain 783, was compared with that of the conventionally attenuated Bartha strain. Strain 783 has deletions in the genes coding for glycoprotein I and thymidine kinase. In experiment 1, which had a 3-month interval between vaccination and challenge exposure, strain 783 protected pigs significantly (P less than 0.05) better against virulent virus challenge exposure than did the Bartha strain. The growth of pigs vaccinated with strain 783 was not arrested, whereas that of pigs vaccinated with the Bartha strain was arrested for 7 days. Of 8 pigs given strain 783, 4 were fully protected against challenge exposure; none of the pigs given strain Bartha was fully protected. In experiment 2, which had a 3-week interval between vaccination and challenge exposure, the growth of pigs vaccinated with strain 783 was arrested for 3.5 days, whereas that of pigs vaccinated with the Bartha strain was arrested for 6 days. In experiment 3, pigs with moderate titer of maternal antibodies were vaccinated twice IM or once intranasally with either strain 783 or Bartha and were challenge-exposed 3 months after vaccination. Pigs given strain 783 twice IM were significantly (P less than 0.05) better protected than were the other pigs. They had growth arrest of only 6 days, compared with 9 days for pigs of other groups, and shed less virus after challenge exposure. Results of this study indicate that the vaccine based on the deletion mutant strain 783 is more efficacious than is the Bartha strain of pseudorabies virus.     

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。     

The effects of challenge on the humoral and cellular immune responses in pseudorabies vaccinated swine.

The effects of challenge exposure on the humoral and cellular immune responses in pseudorabies vaccinated swine were studied in 84 barrows. The pigs were divided into seven groups and challenge exposed to a virulent strain of pseudorabies virus on months 1, 3, 5, 8, 10, 12 and 14 after vaccination. The pigs were vaccinated with commercial attenuated and inactivated pseudorabies virus vaccines. The protection conferred by vaccination was equally effective with both types of vaccines. The levels of cellular and humoral immunity after challenge exposure in pigs vaccinated with either type of vaccine were similar. The cell-mediated immune response can be effectively used for the early detection of pigs exposed to pseudorabies virus. Virus isolation attempts from the brain and spleen in most of the vaccinated pigs were unsuccessful.     

Induced latency in pseudorabies vaccinated pigs.

A latent pseudorabies virus infection was established in pigs despite vaccination with a modified-live pseudorabies virus vaccine. Although the vaccinated pigs developed high concentrations of antibody, virus was recovered from the tonsils and lungs of pigs treated with dexamethasone three months after inoculation with virulent virus. These results may explain why vaccination programs have failed to eliminate the persistence and spread of virulent pseudorabies virus in infected herds.     

Evaluation in swine of a subunit vaccine against pseudorabies

A subunit vaccine against pseudorabies virus (PRV) was prepared by treating a mixture of pelleted virions and infected cells with the nonionic detergent Nonidet P-40 and emulsifying the extracted proteins incomplete Freund's adjuvant. Three 7-week-old pigs without antibodies against PRV were given 2 IM doses of this vaccine 3 weeks apart. Thirty days after the 2nd vaccination, 10(6) median tissue culture infective doses (TCID50) of a virulent strain of PRV were administered intranasally. Tonsillar and nasal swabs were collected daily between 2 and 10 days after challenge exposure. The pigs vaccinated with the subunit vaccine were not found to shed virulent PRV. Two groups of five 7-week-old pigs vaccinated with commercially available vaccines, either live-modified or inactivated virus, and subsequently exposed to 10(6) TCID50 of virulent PRV, shed virulent virus for up to 8 days. The subunit vaccine induced significantly higher virus-neutralizing antibody titers than either the live-modified or inactivated virus vaccine.     

Antibody response of pigs to inactivated monovalent and bivalent vaccines for porcine parvovirus and pseudorabies virus

Groups of pigs vaccinated with an inactivated bivalent vaccine containing porcine parvovirus (PPV) and pseudorabies virus (PRV) developed geometric mean titers (GMT) of humoral antibody for each of the viruses as high or slightly higher than those of other groups of pigs that were vaccinated with inactivated monovalent vaccines containing one or the other of the same viruses. An increase in GMT after challenge exposure of vaccinated pigs to live virus indicated that vaccination did not prevent virus replication. However, an indication that replication was less extensive in vaccinated pigs was provided by the following. Although neither vaccinated nor nonvaccinated (control) pigs had clinical signs after exposure to the live PPV, the effect of vaccination was evident by the fact that GMT were higher in nonvaccinated pigs after exposure than they were in vaccinated pigs. Conversely, all pigs exposed to live PRV had clinical signs, but these signs varied between mild-to-moderate and transient for vaccinated pigs to severe and fatal for nonvaccinated pigs.     

High- and low-challenge exposure doses used to compare intranasal and intramuscular administration of pseudorabies virus vaccine in passively immune pigs.

We compared 3 modified-live pseudorabies virus (PRV) vaccine strains, administered by the intranasal (IN) or IM routes to 4- to 6-week-old pigs, to determine the effect of high- and low-challenge doses in these vaccinated pigs. At the time of vaccination, all pigs had passively acquired antibodies to PRV. Four experiments were conducted. Four weeks after vaccination, pigs were challenge-exposed IN with virulent virus strain Iowa S62. In experiments 1 and 2, a high challenge exposure dose (10(5.3) TCID50) was used, whereas in experiments 3 and 4, a lower challenge exposure dose (10(2.8) TCID50) was used. This low dose was believed to better simulate field conditions. After challenge exposure, pigs were evaluated for clinical signs of disease, weight gain, serologic response, and viral shedding. When vaccinated pigs were challenge-exposed with a high dose of PRV, the duration of viral shedding was significantly (P less than 0.05) lower, and body weight gain was greater in vaccinated pigs, compared with nonvaccinated challenge-exposed pigs. Pigs vaccinated IN shed PRV for fewer days than pigs vaccinated IM, but this difference was not significant. When vaccinated pigs were challenge-exposed with a low dose, significantly (P less than 0.05) fewer pigs vaccinated IN (51%) shed PRV, compared with pigs vaccinated IM (77%), or nonvaccinated pigs (94%). Additionally, the duration of viral shedding was significantly (P less than 0.05) shorter in pigs vaccinated IN, compared with pigs vaccinated IM or nonvaccinated pigs. The high challenge exposure dose of PRV may have overwhelmed the local immune response and diminished the advantages of the IN route of vaccination.(ABSTRACT TRUNCATED AT 250 WORDS)     

Vaccination against pseudorabies with glycoprotein gI+ or glycoprotein gI- vaccine

Subunit pseudorabies vaccines that contained only purified glycoproteins of either of 2 strains of pseudorabies virus (PRV) were prepared and subsequently tested for safety and efficacy. The strains of virus used for vaccine production differed in at least 2 properties. One strain (Kojnok) was virulent for pigs and was believed to code for the entire complement of viral glycoproteins. The other (Kaplan) was a deletion mutant that was unable to code for structural viral glycoproteins gI and gp63. Purified glycoproteins were dispersed in an oil-in-water emulsion and were administered IM to pigs. Both vaccines were found to be safe and effective immunogens. Neither caused any local or general reactions, as verified by examination of the injection site (local safety) and by vaccination of pregnant sows in PRV-infected and noninfected herds. Sows vaccinated with the gI+ or gI- vaccine protected their pigs at levels of 93 and 92%, respectively, against a severe challenge exposure that killed 98% of pigs born from nonvaccinated sows. Vaccinated pigs were tested for active immunity by intranasal challenge exposure with the NIA 3 strain. Protection was quantitated by measuring the relative daily weight difference, expressed in percent per day, between vaccinated and control pigs during the first week after challenge exposure (delta G7); the estimated differences were 2.25 and 2.13% for gI+ and gI- vaccines, respectively. The absence of gI and gp63 did not affect the efficacy of this type of subunit glycoprotein vaccines.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of experimental infection with pseudorabies (Aujeszky's disease) virus on pigs with maternal immunity from vaccinated sows.

Live-virus and inactivated-virus vaccines were used to immunize sows against pseudorabies (Aujeszky's disease) virus. To test the efficacy of the vaccination, 53 pigs of different ages were taken from the 1st and the 2nd litters of vaccinated sows and placed separately in isolation units. The pigs were challenge exposed with virulent pseudorabies virus and examined for clinical signs, virus excretion, and serologic reaction. The challenge inoculum caused severe nervous or respiratory signs of disease in 12 of the 13 control pigs, with a mortality of 76%. The pigs from the 1st litters of sows vaccinated with the live-virus vaccine did not become sick, whereas 2 of the 9 pigs (22%) from the 2nd litters had clinical signs and died of pseudorabies. All pigs from sows vaccinated with the inactivated-virus vaccine remained healthy. The results of virus isolation from oronasal swabs, combined with the serotest results, indicated that challenge exposure of all except 1 of the pigs resulted in a subclinical infection with the formation of active immunity.     

猪伪狂犬病基因缺失活疫苗(SA215)免疫母猪后仔猪母源抗体消长规律及首免日龄

在研究猪伪狂犬病基因缺失活疫苗 (SA 2 15 )免疫接种母猪所产仔猪母源抗体消长规律 ,并绘制其消长曲线的基础上 ,确定了仔猪首免日龄。对免疫母猪所产仔猪于不同日龄进行抗体检测结果表明 ,全部仔猪均获得了高水平母源抗体 ,7日龄高达 2 8.56 ,6 0日龄降至 2 2 .56 ;随着日龄增长 ,抗体水平呈逐渐降低趋势 ,2次大幅下降出现在 14～ 2 1日龄、30～ 6 0日龄。对免疫母猪所产仔猪分别于不同日龄免疫接种 1头份剂量疫苗 (SA2 15 ) ,7d后采血进行抗体检测 ,结果表明 ,7日龄、14日龄、2 1日龄免疫接种仔猪均未引起明显抗体水平升高 ,反而较同期仔猪略有降低 ,30日龄和 6 0日龄免疫接种仔猪则出现了抗体水平的升高 ,其中以 6 0日龄仔猪升高幅度为大。结合母源抗体消长规律 ,确定猪伪狂犬病基因缺失活疫苗 (SA2 15 )免疫母猪所产仔猪的首免日龄为 30日龄