猪IL-2真核表达质粒构建及对PRRSV-ORF5基因疫苗免疫佐剂作用的研究

本研究应用真核表达载体pcDNA3.1（＋）和猪白细胞介素2（IL-2）基因成功构建了IL-2的真核表达质粒（pcDNA-IL-2）,探讨了pcDNA-IL-2作为分子免疫佐剂对猪繁殖与呼吸综合征（PRRS）ORF5基因疫苗（pcDNA-PRRSV-SC2-ORF5）免疫猪的增强作用。经间接ELISA法、MTT比色法及流式细胞仪分别对pcDNA-IL-2与pcDNA-PRRSV-SC2-ORF5共同免疫猪、pcDNA-PRRSV-SC2-ORF5单独免疫猪、pcDNA3.1（＋）空载体和灭菌水免疫对照猪的血清抗PRRSV抗体IgG、外周血T淋巴细胞的增殖活性、CD4^＋和CD8^＋细胞比例进行检测,结果表明pcDNA-IL-2与pcDNA-PRRSV-SC2-ORF5共同免疫猪的IgG含量、外周血T淋巴细胞的增殖活性、CD4^＋和CD8^＋细胞比例与pcDNA-PRRSV-SC2-ORF5单独免疫猪相比有显著差异（P〈0.05）。说明pcDNA-IL-2能显著增强pcDNA-PRRSV-SC2-ORF5基因疫苗免疫猪的体液和细胞免疫应答,可作为PRRSV基因疫苗的良好佐剂。

Construction of Pig IL-2 Eukaryotic Expression Plasmid pcDNA-IL-2 and Its Adjuvant Effect on pcDNA-PRRSV-SC2-ORF5 Gene Vaccine

In this study,pig IL-2 eukaryotic expression plasmid pcDNA-IL-2 was constructed and its adjuvant effect was investigated.Four groups of pigs were immunized with sterilized water,empty vector pcDNA3.1( ),PRRSV-SC2-OFR5 gene eukaryotic expression plasmid pcDNA-PRRSV-SC2-ORF5 and a mixed solution of pcDNA-IL-2 and pcDNA-PRRSV-SC2-ORF5 respectively.Serum of pig in each group was collected at different time post inoculation,and antibody to PRRSV was measured by ELISA.Peripheral T lymphocytes were acquired from a small quantity of blood of each pig,and the activity of lymphocyte proliferation was detected by MTT methods after being cultured with RPMI1640 culture medium.Content of CD 4and CD 8 of peripheral T lymphocytes in each groups of pigs were tested by cytospectrometry.Results showed that the antibody and peripheral T lymphocytes level,content of CD 4,CD 8 cell of the pigs immunized with both pcDNA-IL-2 and pcDNA-PRRSV-SC2-ORF5 were significantly higher than that of the pigs immunized with pcDNA-PRRSV-SC2-ORF5 alone,indicate that plasmid pcDNA-IL-2 can be used as a adjuvant to enhance PRRS gene vaccine.