猪圆环病毒2型Cap蛋白、猪肺炎支原体和副猪嗜血杆菌三联灭活疫苗的制备及安全性和有效性评价

Preparation,safety and efficacy evaluation of inactivated trivalent vaccine against porcine circovirus type 2 Cap protein,Mycoplasma hyopneumoniae and Haemophilus parasuis

猪圆环病毒2型(PCV2)病毒病、猪支原体肺炎以及猪格拉瑟氏病在我国猪群中广泛存在,常见三者的混合感染,给养猪业造成了重大经济损失。目前尚无用于3种疫病防控的联合疫苗,本研究以杆状病毒表达的PCV2 Cap蛋白、猪肺炎支原体(Mhp)抗原、副猪嗜血杆菌(HPS)4型和5型抗原,配合水溶性佐剂制备三联灭活疫苗,并进行安全性和有效性评价。结果显示,在安全性检验中,免疫猪精神、采食、呼吸、粪便和行为均未见异常,与对照猪无显著性差异;接种疫苗后猪体温有一过性升高,24 h后恢复正常,未见局部和全身不良反应。在血清抗体监测中,二免后14 d,免疫组PCV2 Cap蛋白ELISA抗体全部转阳,S/P值为1.291±0.091,对照组抗体为阴性(S/P值<0.4);免疫组Mhp ELISA抗体全部转阳,S/P值为1.133±0.150,对照组抗体为阴性(S/P值<0.4);免疫组HPS 4型和5型血清微量平板凝集试验(MAT)抗体效价均达到1∶16以上,对照组抗体为阴性(MAT抗体效价<1∶4)。在攻毒保护试验中,疫苗对PCV2强毒的保护率为4/5(80%);Mhp强毒攻击后免疫猪肺炎病变平均减少率为61.35%(>60%);疫苗对HPS 4型强毒的保护率为5/5(100%),对HPS 5型强毒的保护率为4/5(80%)。本研究试制的PCV2 Cap蛋白、Mhp、HPS三联灭活疫苗免疫仔猪产生了针对3种病原的特异性抗体,可提供对3种病原强毒攻毒的保护。

The porcine circovirus type 2 associated disease,swine Mycoplasma pneumoniae and Glasser?s disease are widespread in pig herds in China,and the mixed infection is especially serious,causing great economic losses in swine industry.There is no combination vaccine available for the control of the three epidemics.PCV2 Cap protein,Mycoplasma hyopneumoniae antigen,Haemophilus parasuis serotypes 4 and 5 antigens were expressed by a baculovirus expression system,then they were combined with water-soluble adjuvant to prepare trivalent inactivated vaccine,and its safety and immune efficacy were evaluated in piglets.The results showed that in the safety test,the spirit,feeding,respiration,feces,and behavior of all immunized pigs were normal,and there was no significant difference between the control group and the immunized group,no local or systemic adverse reactions were observed.On the 14 th day after the secondary immunization,the S/P values of PCV2 Cap ELISA antibody titers were 1.291±0.091 in all the immunized group,and were negative(S/P<0.4)in the control group;the S/P values of Mhp ELISA antibody titers were1.133±0.150 in the immunized group and were negative(S/P<0.4)in the control group and the titers of HPS 4 and 5 MAT antibody were more than 1∶16 in all the immunized group and were less than 1∶4 in the control group.In the protection experiment,the protective efficacy against PCV2 challenge was 4/5(80%),the lung lesion rate of immunized pig against Mhp challenge was reduced by 61.35%(>60%);the protective efficacy against HPS 4 and HPS 5 challenge was 5/5(100%)and 4/5(80%).In conclusion,the pigs immunized with the trivalent inactivated vaccine produced specific antibodies against porcine circovirus type 2,Mycoplasma hyopneumoniae,and Haemophilus parasuis,indicating that the vaccine can provide good protection against the three pathogens.