猪圆环病毒2型ORF2与T细胞表位重组腺病毒的免疫保护性研究

Study on immune protection of the recombinant adenovirus expressing ORF2 and T lymphocyte epitope of porcine circovirus type 2

为了评估联合表达猪圆环病毒2型(PCV2)ORF2基因和具有免疫原性的T细胞表位(T cell epitope,TCE)基因的重组腺病毒rAd-ORF2-TCE的免疫保护效果,将20头抗体和核酸均为阴性的断奶仔猪随机分为4组,包括2组免疫组、攻毒对照组和阴性对照组。2组免疫组分别免疫重组腺病毒rAd-ORF2-TCE和rAd-ORF2,2周后加强免疫1次,一免后第28天攻毒。通过PCV2特异性抗体水平的检测以及血清中和试验评估疫苗的体液免疫反应水平,通过外周血T淋巴细胞亚群的动态变化以及细胞因子分泌水平评估疫苗免疫诱导的细胞免疫反应水平。结果表明,与其他对照组比较,重组腺病毒rAd-ORF2-TCE能够诱导猪体产生更为强大的体液免疫和细胞免疫水平。攻毒试验结果表明,rAd-ORF2-TCE能够有效抵抗PCV2感染。本试验结果进一步证实了构建的重组腺病毒rAd-ORF2-TCE能够有效地诱导猪产生足够的免疫保护能力。

To evaluate the immune protection of the recombinant adenovirus encoding the ORF2 and immunodominant T cell epitope genes of porcine circovirus type 2(PCV2),20piglets(free of PCV2 specific antibody and PCV2DNA)were randomly divided into four groups,including two vaccinated groups and two control groups.Piglets in the vaccinated groups were immunized intramuscularly with rAd-ORF2-TCE and rAd-ORF2 respectively,and boosted once two weeks later.PCV2 challenge was conducted on day 28post-1st-vaccination.To evaluate the humoral immune response after immunization and challenge,the levels of PCV2 specific antibodies and PCV2-neutralizing antibodies were checked.The changes of CD4+,CD8+T lymphocyte number and the levels of IFN-γand IL-2were analyzed to investigate the cellular immune response after immunization and challenge.In result,the rAd-ORF2-TCE immunization could induce significantly stronger humoral and cellular immune responses than others.The recombinant adenovirus rAdORF2-TCE could resist effectively the infection of PCV2-associated diseases.The results further confirmed that the recombinant adenovirus rAd-ORF2-TCE could effectively stimulate piglets to produce enough immune protection.