共表达鸡IL-6和H5亚型禽流感病毒HA基因重组鸡痘病毒免疫抗体消长规律及免疫效力研究

Antibody Dynamics and Protective Efficacy of Recombinant Fowlpox Virus Co-expressing Cytokine IL-6 Gene and HA Gene of H5 Subtype Avian Influenza Virus

为评价共表达鸡IL-6和H5亚型禽流感病毒HA基因重组鸡痘病毒(rFPV-AIH5AIL6)的免疫抗体消长规律及免疫效力,将重组病毒通过颈部皮下注射和翅部皮下注射2种不同的免疫途径来免疫鸡群,结果发现,2种免疫途径中,重组鸡痘病毒对鸡体质量增加均无影响,而野生型鸡痘病毒均可抑制鸡体质量增加。翅部皮下注射疫苗组能够产生较高的血凝抑制(HI)抗体水平,免疫21d后抗体水平达到高峰,28d后开始下降,49d时仍保持在一定的水平。免疫SPF鸡21d后攻毒,表明该重组病毒能使经滴鼻攻毒的SPF鸡抵抗H5亚型AIV的致死性攻击,保护率为95%,与油苗组相同,与单表达H5亚型禽流感病毒HA基因重组鸡痘病毒组(40%)差异显著;攻毒后3、5、7d采集喉头、泄殖腔棉拭子检测排毒情况,结果发现第3天排毒率最高,其中rFPV-AIH5AIL6免疫组排毒率为最低,显示IL-6在rFPV-AIH5IL6免疫过程中起到了免疫佐剂的作用,这为研制新型的禽流感重组鸡痘病毒疫苗奠定了基础。

In order to evaluate the antibody dynamic in different immune routes and immune protection of the recombinant fowlpox virus co-expressing cytokine IL-6 gene and HA gene of H5 subtype avian influenza virus（rFPV-AIH5AIL6）.Groups of 10-day-old SPF chickens were inoculated by subcutaneous route in the back of neck and wings route with inoculums containing rFPV-AIH5AIL6.There was no significant difference in body weight between the group of rFPV-AIH5AIL6 and the normal control group,but the body weight in group of wild type strain was lower than that of the normal control group.The result of HI antibodies showed that the chickens inoculated subcutaneously by wing route produced higher level HI antibody.HI antibody induced by rFPV-AIH5AIL6 was higher than that induced by rFPV-AIH5A.HI antibody reached a peak at 21 days post vaccination,decreased at 28 days post vaccination,and remained at a certain level at 49 days post vaccination.Another Group of 10-day-old SPF chickens was inoculated by subcutaneous route in wings with inoculums containing rFPV-AIH5AIL6.The chickens were challenged with H5 subtype avian influenza virus at 21 days post vaccination.The protection indexes of groups immunized with rFPV-AIH5AIL6 and killed vaccine were 95%,significantly higher than that of other groups.The result of virus shedding showed that the shedding rate of chickens immunized with rFPV-AIH5AIL6 was the lowest.In summary,chicken IL-6 could improve the immune efficacy against AI when it was co-expressed with HA gene in recombinant fowlpox virus.This study paves the way for further development of a new AIV recombinant vaccine.