为检测禽多杀性巴氏杆菌(P.multocida)外膜蛋白H基因的免疫效果,本研究利用PCR技术扩增禽P.multocida的omph基因片段,并克隆于pcDNA3.1(+)中构建重组质粒pOMPH,经体外表达检测后进行动物免疫,实验动物共分4组:pOMPH组、弱毒疫苗组、pcDNA3.1(+)空载体组和PBS对照组.免疫后对各组鸡进行免疫指标检测,并于三免后两周进行攻毒.结果显示,pOMPH免疫组和弱毒疫苗免疫组血清抗体水平持续上升,与两对照组相比差异极显著(P＜0.01),并且pOMPH免疫组血清抗体水平明显高于弱毒疫苗组(p＜0.05).淋巴细胞增殖试验结果也表明,pOMPH和弱毒疫苗组的刺激值(SI值)极显著高于两对照组(p＜0.01),并且重组质粒组高于弱毒疫苗组.免疫鸡外周血淋巴细胞产生的IFN-γ极显著高于两对照组(p＜0.01),并且pOMPH组高于弱毒疫苗组(P＜0.05).攻毒后pOMPH组和弱毒疫苗组的保护率分别为66.7％和73.3％,表明pOMPH虽然可以为免疫鸡提供一定的保护,但效果不如商品化的弱毒活疫苗,还需采取措施进一步增强其免疫原性.%To investigate the immune efficacy of DNA vaccine encoding out membrane protein H (OmpH) of avian Pasteurella multocida, the omph gene was cloned into the eukaryotic expression vector pcDNA3.1 (+) to construct the recombinant plasmids pOMPH. The immune responses to pOMPH were evaluated based on serum antibody titers, lymphocyte proliferation assay and titers of the cytokines IFN-γ The protective efficacy following challenge with a virulent avian P. multocida strain was evaluated based on protection rate. The result showed that a significant increase in serum antibody levels was detected in chickens vaccinated with pOMPH and attenuated live vaccine (p＜0.01). The lymphocyte proliferation (SI values) and the levels of IFN-γ were higher in chickens immunized with pOMPH than in attenuated live vaccine. Furthermore, pOMPH vaccine provided partial protection to the vaccinated chickens (66.7%); however, the protective efficacy was inferior to that provided by attenuated live vaccine (73.3%). This finding might be useful for the development of avian P. multocida novel vaccines.
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