猪传染性胃肠炎病毒TH-98株S基因核酸疫苗的构建及其免疫效力

Construction of nucleic acid vaccines containing S gene from TGEV isolate TH-98 and their immune effect in mice

利用DNA重组技术,将编码猪传染性胃肠炎病毒(TGEV)TH-98株的全长S基因和主要抗原位点的Sa片段分别插入真核表达载体pCI的多克隆位点中。应用酶切、PCR方法鉴定阳性重组子pCI-Sa和pCI-S。将昆明鼠随机分成A、B、C 3组(A组为pCI-Sa免疫组、B组为pCI-S免疫组、C组为pCI载体对照组),每组35只,每只鼠肌肉注射100μg,免疫3次,每次间隔2周。于初次免疫后第0、14、21、28、354、2 d采血,用ELISA检测血清抗体动态变化,流式细胞仪检测外周血CD4+和CD8+T细胞数量变化。结果表明,重组真核表达载体均能诱导免疫鼠产生特异性的体液免疫及细胞免疫应答,而且pCI-Sa的免疫效果优于pCI-S。

A full length spike（S） gene and a fragment Sa, encoding major antigenic sites, of transmissible gastroenteritis virus（TGEV） strain TH-98 were cloned into the multiple cloning sites of the eukaryotic expression vector pCl, respectively. The recombinant vaccines pCI-Sa and pCI-S were verified with restriction digestion and PCR amplification. Kunming mice were divided randomly into Groups A, B and C of 35 mice each. Each mouse was injected intramuscularly with 100μg of pCI-Sa, pCI S and pCI, respectively. All groups were inoculated three times with the same volume at 2 week interval for improving immunization effect. On days 0, 14, 21, 28, 35 and 42 post-immunization, peripheral blood samples of the immunized mice were collected and subjected to antibody detection by ELISA, and quantitative analysis of CD4^＋ and CD8^＋ T cells by FACS. Results showed that both pCI-Sa and pCI S induced specific humoral and cellular immune responses, but pCI-Sa was better than pCI-S.