DNA免疫防制鸡传染性支气管炎的探索研究

DNA Immunization Elicits VN Antibody to IBV and Prevents IBV Shedding from Infectious Chicken

ORF完整的IBV类M4 1株S1基因cDNA插入真核表达质粒pCICMV启动子下游多克隆位点 ,构成pCIS1用于 1周龄SPF雏鸡的DNA免疫试验。试验鸡每羽腿部肌肉注射pCIS1DNA10 0 μg ,2周后加强免疫一次。二次免疫 2周后 ,人工感染IBVH52 株。结果 ,IBV人工感染后第 4天气管_泄殖腔棉拭子鸡胚病毒分离阳性者 ,免疫试验组为 1/ 6 ,而对照组为 6 / 6 ;鸡胚病毒中和试验显示 ,二次免疫后临感染前及感染后 1周同组混合血清中和抗体效价试验组均为阳性 ,而对照组均为阴性 ,试验表明 ,IBVS1基因DNA免疫可诱导SPF鸡产生特异的IBV中和抗体 ,并可有效形成阻止相同血清型IBV感染后机体排毒的免疫保护。

This experiment was conducted to explore DNA vaccination against chicken infectious bronchitis(IB).The ORF contact S1 gene cDNA originating from a M41 like isolates was insert into pCI multiple clone site at downstream of CMV promoter-enhancer-intron and upstream of SV40 polyA signal to form S1 expressive plasmid pCIS1 as DNA vaccination to vaccinate 1-week-old chickens.The immune group and control group were intramuscularly inoculated with pCIS1 100μg per chicken and pCI 100μg per chicken respectively,and boosted with same doses after 2 weeks.At 4 weeks after priming,both group chickens were bled for VN antibody detects and challenged with 10 2 ELD 50 IBV H52.Tracheal-cloaca lswabs for virus isolation and second blooding for VN test was sampled respectively at 4 days and 1 week post challenge respectively.Virus isolation revealed all control chickens (5/5) positive while only one pCIS1 inoculated chicken (1/6) positive.In contrast to control group chickens with no detectable VN antibody,the lower VN antibody could be detected in immune test chickens.These results indicated that pCIS1 DNA immunization elicits VN antibody to IBV and prevents IBV shedding from infectious chicken.