猪伪狂犬病基因缺失灭活疫苗(JS-2012-△gI/gE株)的制备及免疫效力评价

本研究将猪伪狂犬病毒双基因缺失毒株(JS-2012-△g I/g E株)用0.15%的甲醛灭活后,与赛彼科公司MONTANIDE ISA201VG佐剂进行乳化,制备成猪伪狂犬病灭活疫苗。为了评价灭活疫苗的免疫效力,15头14日龄的健康仔猪(猪伪狂犬病毒、猪繁殖与呼吸综合征病毒、猪瘟病毒和猪圆环病毒Ⅱ型抗原和抗体均为阴性)随机分成3组,每组5头。第一组猪颈部肌肉接种猪伪狂犬病灭活疫苗(JS-2012-△g I/g E株)每头2 m L,接种后28 d,第一组和第二组同样方式同等剂量接种猪伪狂犬病灭活疫苗(JS-2012-△g I/g E株),第三组猪作为对照。第二次免疫后d 28,三组实验猪均滴鼻接种PRV JS-2012第5代强毒,每头105.0TCID50/2 m L。攻毒后0~14 d,每日测量体温并记录临床症状。通过抗体检测和保护效率来评价猪伪狂犬病灭活疫苗(JS-2012-△g I/g E株)免疫效力。结果表明,两次免疫(第一组)PRV g B抗体水平明显高于一次免疫(第二组),两次免疫提供了更好的保护效力。     

猪伪狂犬病基因缺失灭活疫苗(JS-2012-△gI/gE株)最小免疫剂量测定

为了确定猪伪狂犬病基因缺失灭活疫苗(PRV JS-2012-△g I/g E株)的最小免疫剂量,本研究将25头14日龄仔猪(猪伪狂犬病毒、猪繁殖与呼吸综合征病毒、猪瘟病毒、猪圆环病毒2型病原抗体均为阴性)随机分成5组,每组5头。第1~4组分别接种猪伪狂犬病灭活疫苗(PRV JS-2012-△g I/g E株)0.5、1、2、3 m L/头,免疫28 d后各组参照第1次免疫的剂量分别加强免疫1次,第5组实验猪不做处理作为阴性对照。免疫后,每周采集各组猪血清检测抗体水平。待第2次免疫28 d后,5组实验猪均滴鼻接种PRV JS-2012株第5代强毒2 m L,含病毒105.0TCID50/头。结果表明:第1次免疫后14 d,第2~4组猪PRV g B抗体全部转为阳性,而第1组猪在第1次免疫后21 d全部转阳。攻毒后,第1组有1头猪发病,表现精神沉郁、厌食和轻微神经症状,其余4头猪有一过性的发热,无任何其他异常临床表现,保护率为80%;第2~4组,实验猪只有一过性的发热,无任何其他异常临床表现,保护率为100%;第5组猪在攻毒后48 h,体温迅速上升到41℃以上,并表现为明显的精神沉郁、厌食和神经症状,发病率为100%,死亡率为40%。由此确定猪伪狂犬病灭活疫苗(JS-2012-△g I/g E株)最小免疫剂量为1 m L/头。     

猪伪狂犬病基因缺失疫苗的制备、安全性、免疫原性、保存期测定及区域试验

为了提供有效的伪狂犬病疫苗，用鸡胚成纤维细胞扩大培养了PrV HB-98突变株（TK^-/gG^-/LacZ^＋），研制了伪狂犬病基因缺失疫苗，并对该疫苗经肌肉接种、经口等免疫途径的最小免疫剂量进行了测定，同时也对4批疫苗的安全性、效力、免疫期和保存期进行了检测；同时将4批疫苗用于免疫23个猪场的母猪、新生仔猪和育肥猪进行区域试验。测定结果表明，疫苗经上述两种途径接种对不同阶段猪的最小免疫剂量均为10^5.0 TCID50；10倍免疫剂量的疫苗对初生仔猪、15日龄仔猪和妊娠母猪是安全的，免疫猪能抵抗强毒的攻击；疫苗在4℃和-20℃下分别可保存6个月和12个月。对伪狂犬病毒抗体阴性的70日龄商品猪和种猪的免疫期为6个月。田间试验表明，4批猪伪狂犬病基因缺失疫苗安全有效，并可用于仔猪发病时的紧急接种。为猪伪狂犬病基因工程疫苗的制备与应用提供了有力的依据。     

猪五大病毒性疫病免疫预防(二)

<正>(接上期)3猪伪狂犬病发病症状为妊娠母猪流产、产死胎或弱仔,新生仔猪出现神经症状且死亡率高,生长育肥猪出现呼吸道症状。对猪伪狂犬病以免疫为本。3.1伪狂犬疫苗伪狂犬疫苗分灭活疫苗和活疫苗,活疫苗又分自然基因缺失活疫苗和人工基因缺失活疫苗。猪伪狂犬病灭活疫苗(鄂A株)灭活前效价指标为107.5TCID50/mL;伪狂犬活疫苗     

貂源伪狂犬病毒DL14/08株免疫原性及其保护效果的研究

为研制貂源伪狂犬病(PR)灭活疫苗,本实验室从疑似患PR的水貂脑组织中分离到一株PR病毒(PRV)DL14/08株(10~(7.10)TCID_(50)/m L),采用甲醛灭活以铝胶为佐剂制备了水貂源PR灭活疫苗。采用水貂和家兔对疫苗进行安全性检验和最小免疫剂量测定,结果显示水貂和家兔的最小免疫剂量均为5×10~(5.6)TCID_(50)/m L;采用研制的PR灭活疫苗和商品化猪用PR灭活疫苗免疫水貂,免疫21 d后平均中和抗体分别为1∶516和1∶348,用相当于100倍半数致死量毒力的分离株病毒攻毒,自制灭活疫苗组保护率为100%,商品化疫苗组保护率为80%。实验结果表明,制备的水貂源PR灭活疫苗抗体水平及攻毒后保护率明显高于商品化疫苗,能够有效保护强毒株对水貂的攻击,可以作为水貂伪PRV预防和控制的候选疫苗株。     

利用CRISPR-Cas9技术和Cre/loxP系统构建猪伪狂犬病病毒gE基因缺失疫苗株

通过对4株伪狂犬病病毒(PRV)流行株进行比较,选择免疫原性最高的HNQYY2012为亲本株,利用CRISPR-Cas9技术和Cre/loxP系统构建带有LoxP位点的HNQYY2012ΔgE/EGFP~+,然后利用环化重组酶(Cre)去除增强型绿色荧光蛋白(EGFP)基因,构建PRV gE基因缺失株HNQYY2012ΔgE。PCR鉴定和测序结果表明,PRV gE基因缺失株构建成功;一步生长曲线表明,HNQYY2012ΔgE增殖速度慢于亲本株,但最高滴度与亲本株相近;HNQYY2012ΔgE和亲本株对小鼠的半数致死量分别为10~(3.8 )TCID_(50)和10~(2.5 )TCID_(50),表明gE基因缺失株毒力降低。制备的灭活疫苗免疫小鼠能完全抵御5LD_(50)和10LD_(50)强毒攻毒。本文利用CRISPR-Cas9技术和Cre/loxP系统成功构建PRV gE基因缺失株HNQYY2012ΔgE,为猪伪狂犬病灭活疫苗的研制提供了参考。     

PRV FB株gE/gI基因缺失株的构建及其灭活疫苗免疫保护效力评价

自2011年以来,新型伪狂犬病病毒(PRV)变异株在我国免疫猪场不断出现,导致目前商品化疫苗免疫效果不佳。为研究PRV FB株gE/gI基因缺失株疫苗防控新型PRV变异株感染的效果,本研究以PRV自然弱毒FB株作为亲本株,通过同源重组的方法构建了PRV g E/gI基因缺失株,将不同代次PRV FBΔgE/gI株与亲本PRV FB株分别接种BHK-21细胞,观察CPE和测定TCID50效价,分析缺失株的遗传稳定性,结果显示FBΔgE/gI株感染BHK-21细胞后产生与亲本株FB相似的CPE,且不同代FBΔgE/gI株的TCID50与亲本株相比均无明显变化。将FB株、FBΔgE/gI株、Bartha-K61株分别接种健康新西兰兔,比较三者的安全性,结果显示,接种BarthaK61株的家兔全部死亡(5/5),接种FB株的家兔死亡2只(2/5),而接种FBΔgE/gI株的家兔全部(5/5)健活,表明FBΔgE/gI株对新西兰兔的致病力较低,安全性更高。将FBΔgE/gI株分别与水相佐剂GEL02和两性佐剂ISA 206制成灭活疫苗免疫绵羊28 d后,采用ELISA法检测各组绵羊的gB和gE抗体,并且以PRV变异株FJ-2012攻毒,评估FBΔgE/gI株灭活疫苗对绵羊的保护效力,结果显示,接种GEL02和ISA 206为佐剂的FBΔgE/gI灭活疫苗绵羊在免疫后28 d,抗体均全部转阳;对照组绵羊在攻毒后6 d内全部死亡(5/5),以GEL02作为佐剂的灭活疫苗组绵羊死亡2只(2/5),而以ISA 206为佐剂的绵羊全部存活(5/5),保护率达到100%,表明以ISA 206作为佐剂的FBΔgE/gI株灭活疫苗能够完全保护绵羊抵御PRV变异株的攻击。本研究首次基于PRV自然弱毒FB株构建的FBΔgE/gI株,与Bartha-K61株相比具有更高的安全性,与佐剂ISA 206制成灭活疫苗免疫绵羊后能够完全抵抗新发变异PRV的攻击,具有完全保护作用。本研究为我国新发变异PRV疫苗的研发提供了新的参考依据。     

猪伪狂犬病灭活疫苗(PRVSX-gE株)对怀孕母猪安全性及繁殖性能的影响

为了确定猪伪狂犬病灭活疫苗(PRVSX-gE株)对怀孕母猪的安全性及繁殖性能的影响,本研究选用3批疫苗对怀孕母猪进行一次单剂量接种、单剂量重复接种及一次超剂量接种的试验。结果显示,肌内注射猪伪狂犬病灭活疫苗(PRVSX-gE株)后,母猪接种部位及全身无不良反应,母猪健康,妊娠正常,无死胎和木乃伊胎,新生仔猪生长发育良好。试验表明,自主研制的猪伪狂犬病灭活疫苗(PRVSX-gE株)对怀孕母猪安全,对怀孕母猪繁殖性能无影响。     

伪狂犬病毒人工感染小鼠模型的建立

为建立伪狂犬病毒(PRV)人工感染小鼠的模型,本研究采用PRV强毒株接种猪、羊及小鼠,疫苗株接种小鼠,应用组织病理技术观察PRV人工感染不同动物导致的组织病变。以1×102~4.5×104TCID50不同梯度剂量PRV强毒株通过滴鼻或皮下接种途径人工感染小鼠,6×104~2.7×105TCID50不同剂量疫苗株皮下接种小鼠,统计各人工感染剂量下小鼠存活率。感染PRV动物脑部病理切片经苏木素-伊红(HE)染色观察,结果显示PRV强毒株及疫苗株接种小鼠后与PRV感染猪、羊后出现相似病理变化,均可导致炎性细胞的浸润及大脑实质内小胶质细胞的增殖。免疫组化染色表明PRV可以感染小鼠脑组织。本研究最终采用小鼠作为实验动物,应用PRV疫苗株,采用1×105TCID50剂量通过皮下注射接种小鼠,在接种后6 d观察病变。该实验模型为进一步研究PRV感染小鼠后的天然免疫机制提供了实验依据。     

膜分离法纯化浓缩猪伪狂犬病疫苗毒的效果

本研究使用不同孔径的陶瓷(有机)膜过滤器,对不合格的猪伪狂犬病毒细胞收获液(病毒含量≤104TCID50/mL)滤除杂蛋白、超滤浓缩、除菌处理得到纯化浓缩的猪伪狂犬病疫苗病毒液;然后对纯化浓缩的猪伪狂犬病疫苗病毒液分别进行杂蛋白去除率检验与无菌检验、病毒含量测定、安全检验、效力检验;将检验合格的纯化浓缩的猪伪狂犬病疫苗病毒液添加保护剂冻干,并对纯化浓缩的猪伪狂犬病冻干活疫苗进行以上各项检验,以及进行免疫猪体内抗体消长变化的检测。结果表明:纯化的猪伪狂犬病疫苗杂蛋白去除率平均达到68.3%以上,病毒含量≥105TCID50/mL,效力检验合格;免疫猪体内抗猪伪狂犬病毒抗体增长幅度比同时期未纯化的常规疫苗显著,其中免疫至84 d时中和抗体效价平均高达40.35稀释倍数左右,比常规疫苗中和抗体效价平均高出14.22稀释倍数。此项研究为畜禽疫苗的纯化提供一定的参考。     

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.     

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)     

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.     

Efficacy of a killed gpX deleted pseudorabies virus vaccine.

Ten inactivated vaccines containing one of four adjuvants and varying concentrations of pseudorabies virus (PRV) antigens were compared in order to select a vaccine suitable for commercial production. A genetically engineered strain of PRV lacking the gene coding for glycoprotein X (gpX) was used in these vaccines. Vaccinated pigs were challenged intranasally with virulent PRV to determine the efficacy of vaccines. Vaccination of pigs with one dose of experimental vaccines adjuvanted with 50% Montanide ISA 50 or 20% Syntrogen induced a protective immunity at least equal to that induced by two commercially available killed PRV vaccines also evaluated. An experimental vaccine containing 20% Syntrogen was selected and further evaluated according to United States Department of Agriculture licensing requirements. None of the pigs vaccinated with this vaccine produced gpX antibodies detectable by the HerdChek: Anti-PRV-gpX assay. Therefore, this assay could differentiate PRV vaccine induced antibodies from antibodies induced by natural exposure when used in conjunction with this killed gpX deleted PRV vaccine.     

Evaluation of a protective immunity induced by an inactivated influenza H3N2 vaccine after an intratracheal challenge of pigs.

A challenge study was conducted to evaluate the safety and efficacy of an inactivated influenza H3N2 virus vaccine combined with Quil A/Alhydrogel mixture under controlled conditions in piglets. Twenty-four piglets from 12 sows were allocated to 2 groups; injected intramuscularly with 2 doses of the tested vaccine or with PBS at 2 wk intervals and challenged intratracheally with 105TCID50 of the H3N2 swine influenza virus 6 d after the 2nd immunization. Clinical and virological parameters were recorded for 4 d after the challenge. The use of the tested vaccine produced high serum hemagglutination-inhibition titers against the swine H3N2 strain virus. This strong immune response suppressed all clinical signs and viral shedding and reduced pulmonary lesions due to the challenge in the vaccinated group, without causing any secondary effects. Our results suggest that the serum HI titers correlated with the degree of protection induced by an inactivated swine influenza H3N2 vaccine.     

重组鸡痘病毒vFV282活疫苗最小免疫剂量及攻毒保护试验

将重组鸡痘病毒vFV282疫苗用生理盐水作10^-1，10^-2，10^-3，10^-4系列稀释，分别免疫7天龄鸡，于免疫后21d，分别用NDV、IBDV和FPV攻毒，观察其保护率，结果除NDV攻毒在10^-4组保护率为40％（4／10），其余各组均为100％（10／10）保护。表明该疫苗的最小免疫剂量≤10^-3TCID50/0.02mL。     

猪伪狂犬病病毒灭活疫苗对猪伪狂犬病病毒流行毒株和经典毒株的免疫保护效果评估

为评估猪伪狂犬病病毒（Pseudorabies virus,PRV）灭活疫苗（HN1201-ΔgE株）免疫后对PRV流行毒株和经典毒株的保护效果,本研究对试验猪分别免疫PRV灭活疫苗（HN1201-ΔgE株）和PRV活疫苗（Bartha-K61）,免疫后第0、7、10、14、17、21、24和28天采血测定PRV gB抗体,并分别使用PRV流行毒株HN1201株和经典毒株闽A株测定免疫后第0、7、14、21和28天血清的中和抗体水平,于免疫后第28天分别使用HN1201株和闽A株攻毒并观察,之后测定体温,测定攻毒后第7和14天PRV gE抗体,及攻毒后0~8 d的排毒情况。结果显示,HN1201-ΔgE免疫组较Bartha-K61免疫组gB抗体和中和抗体产生早,且抗体水平较高。两个免疫组试验猪在攻毒后虽然均无明显临床症状,且免疫组织化学检测（IHC）组织中的病毒抗原均为阴性,但HN1201-ΔgE免疫组试验猪脏器未见任何病理损伤,Bartha-K61免疫组试验猪部分脏器具有病理损伤。与未免疫对照组相比,2个免疫组试验猪在HN1201株和闽A株攻毒后,gE抗体转阳时间晚且排毒率低,HN1201-ΔgE免疫组gE抗体水平整体均低于Bartha-K61免疫组,攻毒后排毒检测中,Bartha-K61免疫组于2个毒株攻毒后第3~5天可检测到排毒,而HN1201-ΔgE免疫组全程未检测到排毒。研究结果表明,灭活疫苗（HN1201-ΔgE株）对PRV流行毒株和经典毒株均可提供完全保护。     

伪狂犬病弱毒株的分离鉴定及生物学特性的研究

在流行病学调查中分离到1株病毒,经鉴定为伪狂犬病弱毒株,定名为F971株。分离病毒经克隆纯化后测得其毒价为10^7.59TCID50/ml,通过细胞中和试验表明分离病毒能也有效地被猪伪狂犬病毒闽A株阳性血清中和。病毒在电镜下可以清楚地观察到囊膜及外周纤突。分离株对3日龄乳鼠有一定的致病力,但对家兔、3日龄乳猪及妊娠母猪都有很高的安全性。用不同的剂量10^0、10^-1、10^-2肌肉注射3日龄乳猪后14天用10^5.7TCID50伪狂犬病强毒攻击,所有试验仔猪均得到保护。用分离株免疫母猪,其后代可获高滴度的母源抗体,15日龄的仔猪能抵御10^5.7TCID50强毒的攻击。用ELISA普查试剂盒测定免疫猪抗体,结果均为阳性,而用g^1-ELISA试剂盒测定抗体时,结果均为阴性。证明分离株具有缺损g^1糖蛋白的特性。综合上述特性,确定F971为1株g^1糖蛋白缺损的猪伪狂犬病弱毒株。     

Effect of intratracheal challenge of fattening pigs previously immunised with an inactivated influenza H1N1 vaccine

Intratracheal inoculation of a field isolate of influenza A H1N1 caused high fever, anorexia and dyspnoea in unvaccinated pigs. In a limited study, it was shown that animals vaccinated once with an inactivated influenza A H1N1 strain showed partial protection at challenge, indicated by mild or absent clinical signs and by the suppression of viral replication. There appeared to be a correlation between the hemagglutination-inhibition titers of the serum of vaccinated pigs and the degree of protection. Animals vaccinated with two spaced injections were completely protected at challenge. Viral replication was inhibited in their respiratory tract since no virus was isolated from animals at slaughter and no increase in antibody titer was observed in challenged vaccinates followed serologically. It was concluded that vaccination of swine against influenza with an inactivated vaccine can result in a protective immunity in the respiratory tract. The New Jersey vaccine strain could protect against swine influenza strains (H1N1) currently prevalent in several European countries.