猪圆环病毒2型DNA疫苗对小鼠的免疫效果

The construction of PCV2 DNA vaccine and its immune response in mouse

【目的】构建一种猪圆环病毒2型DNA疫苗,并对其免疫效果进行了研究。【方法】将表达猪圆环病毒2型ORF2基因的1套真核表达元件系统克隆插入到质粒载体pMD-18T,构建成pMD-18T-ORF2,转入E.coliDH5α,提取质粒,经肌肉注射途径对Balb/c小鼠分别在第1,14和28天进行免疫,用生理盐水代替pMD-18T-ORF2进行相同操作,作为对照组,通过监测免疫小鼠体液免疫和细胞免疫的状况,评估分析pMD-18T-ORF2免疫的效果。【结果】初次免疫后小鼠血清中特异性抗体水平持续升高,在第14天达到峰值,加强免疫抗体水平无显著变化;试验组脾淋巴细胞体外增值能力较对照组低(P<0.01);免疫pMD-18T-ORF2的小鼠脾脏NK细胞杀伤活性极显著高于对照组(P<0.01);试验组小鼠脾脏中Th细胞含量与对照组小鼠无显著差异(P>0.05),Tc细胞含量显著高于对照组(P<0.05),B细胞含量较对照组有所减小,但差异不显著(P>0.05)。【结论】构建的pMD-18T-ORF2对小鼠能产生相应的免疫反应,且细胞免疫的效果较体液免疫更显著,非特异性免疫亦有提高。

【Objective】 A kind of PCV2 DNA vaccine is constructed and its immune effect is tested.【Method】 A set of eukaryotic expression elements encoding PCV2 ORF2 is inserted into the plasmid vector pMD-18T,constructed the recombinant pMD-18T-ORF2.pMD-18T-ORF2 is transformed into E.coli DH5α to increase its copies.The Balb/c mice are injected intramuscularly with the recombinant plasmid pMD-18T-ORF2 every 14 days three times totally.The control group is injected with physiological saline solution instead.【Result】 The monitoring of antibody indicates that the specific antibody to the protein encoding by PCV2 ORF2 increases within the 14 days after the first injection.But the following immune almost make no use of the level of antibody.Compared with the control group,the spleen lymphocytes proliferative ability have a little descent（P 〈0.01） but the NK cells activities are significantly elevated （P〈0.01）.The percentage of the Tc lymphocytes in spleen is much higher than the control group（P〈0.01）,but the percentage of Th and B lymphocytes have no difference between the two group（P〈0.05）.【Conclusion】 The constructed recombinant pMD-18T-ORF2 has the corresponding immune response to the mice,and cellural immuity is more remarkable than humoral immunity.