牛源荚膜A型多杀性巴氏杆菌疫苗候选株的筛选及鉴定

为了筛选生长快、毒力强、免疫原性好、副反应小的牛源荚膜A型多杀性巴氏杆菌（Pasteurella multocida，Pm）灭活疫苗菌株，本试验选取6株来自不同地区致犊牛肺炎死亡的牛源荚膜A型多杀性巴氏杆菌分离株，测定了培养基生长曲线、小鼠毒力、菌体脂多糖（LPS）含量及各菌株灭活菌苗免疫小鼠和家兔后的抗体效价，并进行了攻毒保护试验。结果显示，分离株Pm2、Pm3、Pm5生长速度较快、毒力较强、LPS含量较多，均含有与毒力和免疫相关的ptfA和fimA基因；免疫小鼠及家兔未发现明显不良反应，在二免后14 d血清抗体达1：64~1：128，强毒攻毒后全部存活，而PBS对照组全部死亡。本试验结果表明，Pm2、Pm3、Pm5均可作为多杀性巴氏杆菌灭活菌苗的候选菌株，其中Pm3作为首选株。

Screening and Identification of Bovine Capsular Type A Pasteurella multocida Vaccine Candidate Strains

In order to screen the inactivated strain of bovine capsular type A Pasteurella multocida, which was fast, virulent, immunogenicity and small side reaction, six strains of bovine capsular type A Pasteurella multocida were collected in different areas. The growth curve of the medium, the virulence of mice, the content of lipopolysaccharide (LPS) and the antibody titer in mice and rabbits immunized with the inactivated bacteria of each strain were determined, and the attack protection test was carried out. The results showed that the growth rate of Pm2, Pm3 and Pm5 isolates were faster, the virulence were stronger and the LPS content were higher. All of them contained ptfA and fimA genes related to virulence and immunity. No significant adverse reactions were found in immunized mice and rabbits, the serum antibody was 1:64 to 1:128 after 14 days of the second immunization, and all animals tested survived after virulent challenge, that in the PBS control group were all died. The results indicated that Pm2, Pm3 and Pm5 could be used as Pm inactivated vaccine candidate strains, and of which Pm3 was the preferred strain.