猪乙型脑炎病毒灭活疫苗(A6株)的制备及免疫保护研究

Study on immunoprotective effects of porcine Japanese encephalitis virus inactivated vaccine(A6 strain)

为了制备猪乙型脑炎病毒(A6株)灭活疫苗,并研究其免疫保护效果,试验将猪乙型脑炎病毒(A6株)在Vero细胞上培养增殖,用β-丙内酯灭活,将检验合格的抗原与206疫苗佐剂乳化制备成猪乙型脑炎病毒灭活疫苗(A6株)。将制备的猪乙型脑炎病毒灭活疫苗(A6株)用PBS稀释成1∶5、1∶50、1∶5003个稀释度免疫小鼠后攻毒,后备母猪肌肉注射猪乙型脑炎病毒灭活疫苗(A6株)后间隔14 d后加强免疫1次,对免疫后备母猪及所产仔猪的中和抗体效价进行测定。同时,进行后备母猪免疫攻毒试验,分为疫苗免疫组和攻毒对照组,母猪妊娠30 d后用猪乙型脑炎病毒(A6株)进行攻毒,攻毒后记录各组母猪临床症状及所产仔猪的健康状况,发病仔猪剖检,观察病变。结果表明:猪乙型脑炎病毒灭活疫苗(A6株)1∶50倍稀释免疫小鼠进行攻毒,保护率可达到80%。后备母猪间隔14 d免疫两次可以产生高水平的中和抗体,而且所产仔猪的中和抗体效价可以维持到30日龄。对妊娠30 d母猪进行攻毒,疫苗免疫组妊娠母猪均正常产仔,仔猪全部健活,全部保护;攻毒对照组妊娠母猪发生流产,产出死胎、木乃伊胎和弱胎,全部发病。发病胎儿剖检,可见脑积水、皮下水肿、胸腔和腹腔积液、淋巴结充血等病理变化。说明猪乙型脑炎病毒灭活疫苗(A6株)具有良好的免疫保护效果。

In order to prepare inactivated porcine Japanese encephalitis virus(A6 strain)and study its immunoprotective effects,in the experiment,porcine Japanese encephalitis virus(A6 strain)was cultured and proliferated on Vero cells,inactivated withβ-propiolactone,and the qualified antigen was emulsified with 206 vaccine adjuvant to prepare an inactivated porcine Japanese encephalitis virus vaccine(A6 strain).The prepared porcine Japanese encephalitis virus inactivated vaccine(A6 strain)was diluted with PBS to 3 dilutions of 1∶5,1∶50,and 1∶500 to immunize mice and then the challenge was carried out.The gilts were intramuscularly injected with porcine Japanese encephalitis virus inactivated vaccine(A6 strain)and boosted once at an interval of 14 days,and the neutralizing antibody titers of the immunized gilts and piglets were determined.At the same time,the challenge test after immunization was carried out on the reserve sows,which were divided into vaccine immunization group and challenge control group.The sows were challenged with porcine Japanese encephalitis virus(A6 strain)after 30 d of gestation,and the clinical symptoms and health status of piglets delivered were recorded in each group after the attack,and the sick piglets were examined by autopsy to observe the lesions.The results showed that the 1∶50-fold dilution of porcine Japanese encephalitis virus inactivated vaccine(A6 strain)was used to immunize mice and then the challenge was carried out;and the protection rate could reach 80%.The gilts were immunized twice at an interval of 14 days to produce high levels of neutralizing antibodies,and the neutralizing antibody titers of the born piglets could be maintained to 30 days of age.The sows were challenged on the 30 th day of gestation,and all the gestating saws in the vaccine immunized group had normal litter,and all the piglets were alive and all of them were protected.On autopsy of the fetus with onset,case changes such as hydrocephalus,subcutaneous edema,pleural and abdominal effusions,and lymph node congestion were seen.The pregnant sows in the challenge control group suffered from miscarriage,stillbirths,mummies and weak fetuses,and all of them were affected.The results suggested that the porcine Japanese encephalitis virus inactivated vaccine(A6 strain)had good immunoprotective effects.