A:L1型鸭源多杀性巴氏杆菌灭活疫苗制备及免疫效力研究

Preparation and Immunological Study of Inactived Vaccine of Type A:L1 Pasteurella multocida from Ducks

【目的】制备鸭多杀性巴氏杆菌灭活疫苗,有效控制贵州省鸭多杀性巴氏杆菌发生和流行。【方法】以实验室分离保存的A:L1型多杀性巴氏杆菌地方流行株为菌种,通过涂板法测定该菌株生长曲线,并采用改良寇氏法计算该菌株对鸭的半数致死量(median lethal dose,LD_(50)),将该菌培养至终浓度为1×10^(10)CFU/mL后分别制备白油佐剂灭活疫苗和卡波姆佐剂灭活疫苗,经疫苗质量检验后进行免疫雏鸭试验;通过攻毒保护试验评价比较两种疫苗的保护率,并对攻毒试验鸭肝脏、肺脏、脾脏进行病理组织学观察。【结果】A:L1型多杀性巴氏杆菌疫苗株培养至18 h到达峰值,活菌数可达1.0×10^(10)CFU/mL;LD_(50)为5 CFU;制备的两种疫苗安全性良好;攻毒保护试验结果显示,一免后卡波姆佐剂灭活疫苗免疫保护率可达62.5%,高于白油佐剂灭活疫苗(50.0%)及商品灭活疫苗(50.0%)。二免后卡波姆佐剂灭活疫苗优势更为明显,免疫保护率可达87.5%,高于白油佐剂灭活疫苗(75.0%)及商品灭活疫苗(62.5%)。病理组织学结果显示,一免后卡波姆佐剂灭活疫苗能对肺脏提供较好的保护效果,二免后在肝脏、肺脏和脾脏的保护效果上,卡波姆佐剂灭活疫苗组优势明显。【结论】利用贵州地区流行的A:L1型菌株所制备的卡波姆佐剂灭活疫苗免疫效果明显,能对贵州地区多杀性巴氏杆菌病的防控起到重要作用。

【Objective】The inactivated Pasteurella multocida vaccine was prepared to effectively control the occurrence and prevalence of Pasteurella multocida in ducks in Guizhou province.【Method】The local epidemic strain of A:L1 type Pasteurella multocida,isolated and preserved in the laboratory,was used as the strain.The growth curve of the strain was determined by the plating method and the median lethal dose(LD_(50))was calculated by improved Karber’s method.After the bacteria were cultured to a final concentration of 1×10^(10) CFU/mL,the oil adjuvant inactivated vaccine and carbomer adjuvant inactivated vaccine were prepared respectively,and then the immunized duckling test was conducted after the vaccine’s quality was inspected.The protection rate of the two vaccines were evaluated and compared by the challenge protection test,and the histopathological observation was performed on the liver,lung and spleen of the ducks in the challenge test.【Result】The vaccine strain of A:L1 type Pasteurella multocida reached to the higestaed after 18 h,the concentration of viable bacteria was reached to 1.0×10^(10) CFU/mL,and the LD_(50) was reached to 5 CFU.The safety of the two vaccines was qualified.The challenge protection test results showed that after first immunization,the immune protection rate of the carbomer adjuvant inactivated vaccine could reached 62.5%,which was higher than that of the oil adjuvant inactivated vaccine(50.0%)and the commercial inactivated vaccine(50.0%).After the second immunization,carbomer adjuvant inactivated vaccine had obvious advantages,and the immune protection rate could reached 87.5%,which was higher than that of oil adjuvant inactivated vaccine(75.0%)and commercial inactivated vaccine(62.5%).The histopathological results showed that carbomer adjuvant inactivated vaccine could provide best protective effects on the lung after the first immunization,and in terms of the protective effects of liver,lung and spleen after the second immunization,the carbomer adjuvant inactivated vaccine group had obvious advantages.【Conclusion】The carbomer adjuvant inactivated vaccine prepared by using the A:L1 strains prevalent in Guizhou had obvious immune effects,which could play an important role in the prevention and control of Pasteurellosis multocida in Guizhou.