Ubiquitin基因介导下的PRRSV GP5基因免疫特性研究

目的：探讨泛素基因对GP5基因免疫的影响。泛素-蛋白酶体途径是一种高效蛋白降解途径，主要负责真核细胞内蛋白选择性降解。方法：本研究将ORF5DNA片段克隆到含泛素（Ub）基因的表达载体pCMV-Ub和pCMV载体，构建成重组质粒pCMV—Ub-GP5和pCMV-GP5。两种质粒DNA肌肉注射免疫BALb／c小鼠后，分别检测体液免疫反应和细胞免疫反应，比较GP5单基因和Ub—GP5融合基因DNA免疫所诱生免疫应答的强度。结果：二者均可诱生PRRSVELISA抗体和中和抗体，其抗体水平无明显差别，但Ub-GP5融合基因诱生的淋巴细胞反应和CTL反应明显高于GP5基因。结论：泛素基因可以促进GP5诱生细胞免疫反应。

Immune Responses Induced by DNA Vaccination of Ubiquitin-conjugated GP5 Protein Gene of Porcine Respiratory and Reproductive Syndrome Virus

Objective:To evaluate the immunity of GP5 protein gene of porcine respiratory and reproductive syndrome virus(PRRSV).The ubiquitin-proteasome pathway is an efficient pathway for protein degradation.It's mainly responsible for the selective degradation of many proteins in eukaryotic cells.Methods:The GP5 protein gene was amplified with PCR and cloned into both pCMV-Ub containing mice ubiquitin gene and pCMV plasmid,respectively,and two recombinant plasmids,pCMV- Ub-GP5 and pCMV-GP5,were constructed and identified.Mice were immunized with the two kinds of plasmids four times with frequency of 15 days,and the serum antibodies and cellular immune response to PRRSV were estimated with ELISA,virus neutralizing test,lymphocyte proliferation assay and GTL test,respectively.Results:There were not much more differences between the two plasmids in antibody responses.But the fusion gene DNA induced stronger cellular immune responses than single gene DNA did.Conclusion:It indicated that Ub conjugation did improve the cellular immune response to GP5 in mice.