本研究旨在对本实验室所构建的表达鸡传染性支气管炎病毒(IBV) S1蛋白的重组假型杆状病毒(Ac-V-S1)的免疫保护效果进行探讨.以2×109 pfu剂量的重组假型杆状病毒(Ac-V-S1)腿部肌肉注射7日龄SPF雏鸡,21日龄加强免疫1次.血清抗体检测表明,灭活疫苗组诱导的IBV特异性ELISA抗体水平最高,极显著高于其它试验组(P＜0.01),其次是Prime-boost组(先免疫Ac-V-S1后免疫poly156S1亚单位疫苗)和Ac-V-S1组；但在细胞免疫水平方面,Ac-V-S1免疫组表现出较强的优势,免疫应答反应极显著的高于其它免疫组(P＜0.01),然后是Prime-boost组和杆状病毒野毒对照组.二免后2周用IBV M41强毒进行攻毒保护试验.结果表明,Ac-V-S1、Ac-V-EGFP、poly156S1亚单位疫苗组的保护率分别为55％(6/11)、27％(3/11)、37％(4/11),而采用Prime-boost免疫组的保护率为64％(7/11),略低于免疫保护率为73％的常规灭活疫苗(8/11).结果显示:重组杆状病毒Ac-V-S1具有较好的免疫效果,而且在细胞免疫方面具有较强优势,可以弥补重组杆状病毒在体液免疫水平的不足,而Prime-boost免疫策略能更进一步提高重组杆状病毒免疫效果,为将重组杆状病毒发展为经济有效的IBV基因工程疫苗奠定基础.%This experiment was conducted to study the immune protection effect of a Recombinant Pseudotype Baculovirus expressing the SI protein of infectious bronchitis virus. Sixty-six 7-day-old SPF chickens were randomly divided into 6 groups, and were inoculated with Ac-V-EGFP (2×109 pfu), Ac-V-S1, poly156S1 subunit vaccine, commercialized inactivated vaccine (M41) and PBS (control) respectively, boosted immunization was conducted at day 21. The results showed that, in the humoral immune, the inactivated vaccine group induced the highest level of IBV-specific ELISA antibody, significantly higher than other groups(P<0. 01), in turn were prime-boost group and the Ac-V-S1 group; in cellular immunity, the Ac-V-S1 immunized group showed significantly higher than other groups(P<0. 01) , in turn were prime-boost group and the wild-type baculovirus group. Two weeks after the second immunization, the chickens were challenged with IBV M41 strain. The post-challenge results showed that the protective rate of Ac-V-S1, Ac-V-EGFP, and poly156S1 subunit vaccine were 55% (6/11), 27% (3/11), 37% (4/11), respectively, and the protective rate of the prime-boost immunity group was 64% (7/11), a little lower than the regular inactivated vaccine group 73% (8/11). Results demonstrated that the recombinant baculovirus Ac-V-S1 showed better effects on cellular immunity, which can make up for deficiencies in humoral immunity, and the prime-boost immunization strategy can further enhance the immune effect of recombinant baculovirus. This study laid the foundation of the research of recombinant baculovirus as genetic engineering vaccine of IBV.
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