鸡β-防御素-5的制备及其对HVT冻干疫苗免疫增强效果的分子佐剂效应的研究

Preparation of chicken β-defensin-5 and the molecular adjuvant effect on immune enhancement of lyophilized HVT vaccine

为研究β-防御素-5(Av BD5)分子佐剂与HVT冻干疫苗联合免疫雏鸡后是否具有免疫增效功能,笔者构建了重组真核表达质粒pcDNA3.1(+)-Av BD5,制备了分子佐剂,将1日龄雏鸡随机分组分别注射PBS、空质粒pcDNA3.1(+)、分子佐剂、CVI988疫苗、HVT冻干疫苗以及分子佐剂联合HVT冻干疫苗。在鸡7、14、21、28、35日龄时,每组随机选取5只鸡,分别对其免疫器官指数、T淋巴细胞及血清抗体的含量进行计算或检测。结果显示,Av BD5基因扩增后测序,与数据库Av BD5基因同源性为100%。分子佐剂可促进脾和法氏囊的生长,并显著增加外周血中CD3^(+)、CD4^(+)T淋巴细胞的数量。与HVT冻干疫苗联合免疫后,可以显著增加血清中Ig G抗体的含量以及MD抗体的水平。结果表明,成功构建出重组表达质粒pcDNA3.1(+)-Av BD5,作为分子佐剂具有一定的免疫增强能力,可提高HVT冻干疫苗的免疫效力。

The purpose of this study was to investigate whether β-defensin-5(AvB D5) molecular adjuvant and HVT freeze-dried vaccine have immune synergistic function after injecting chicks.At first,the recombinant eukaryotic expression plasmid pcD NA3.1(+)-AvB D5 was constructed and extracted to prepare the molecular adjuvant.Then,the 1-day-old chicks were randomly divided into 6 groups and they were injected with PBS,empty plasmid pcD NA3.1(+),molecular adjuvant,CVI988 vaccine,HVT freeze-dried vaccine,and molecular adjuvant combined HVT freeze-dried vaccine,respectively.Whereafter,5 chickens were randomly selected from each group at 7,14,21,28,and 35 days.At last,the immune organ index,T lymphocyte,and serum antibody levels were measured or detected,respectively.The sequencing result showed that the amplified AvB D5 gene had 100% homology with the AvB D5 gene in the database.Molecular adjuvants could promote the growth of the spleen and bursa,and significantly increase the number of CD3^(+)and CD4^(+)T lymphocytes in peripheral blood.It could also improve IgG and MD antibody levels in the serum when molecular adjuvants combined with HVT freeze-dried vaccine.The recombinant expression plasmid pcDNA3.1(+)-AvBD5 was successfully constructed,and it had a significant immune enhancement ability as a molecular adjuvant,which could improve the immune efficacy of HVT freeze-dried vaccine.