猪生殖与呼吸综合征病毒GP5蛋白抗原表位基因的表达及其表达产物的抗原性

为了确定猪生殖与呼吸综合征病毒GP5蛋白A、B抗原表位之间的相互关系和对免疫的影响,应用PCR方法扩增出A、B抗原表位基因并分别克隆于原核和真核表达载体中。原核重组质粒表达的重组蛋白经Western-blotting检测证明,该重组蛋白具有良好的抗原性。将重组蛋白和真核表达质粒免疫小鼠,前者可诱导产生针对PRRSV的特异性ELISA抗体,但是此抗体没有中和活性;后者不能诱导免疫小鼠产生PRRSV特异性抗体。结果表明,中和抗体的产生不但与A、B表位的空间构象有很大的关系,如果蛋白质分子质量过小也不能诱导机体产生有效的免疫反应。

Expression of the genes encoding epitopes of GP5 protein of porcine reproductive and respiratory syndrome virus and antigenicity of the expressed product

To elucidate the relationship between epitopes A and B of GP5 protein of porcine reproductive and respiratory syndrome virus(PRRSV) and their effects on immunogenicity,the genes encoding epitope A and B were amplified by PCR and cloned into prokaryotic and eukaryotic expression vectors,respectively.Western-blot analysis confirmed that the prokaryoticly-expressed recombinant proteins had excellent immunogenicity.Mice inoculated with the protein could produce the antibody against PRRSV,but the antibody did not have the specific neutralizing activity.Meanwhile,mice immunized with the eukaryotic expression plasmid pcDNA3-GP5AB could not produce the specific antibody against PRRSV.The result indicated that the induction of the neutralizing antibody was associated mainly with the spatial conformation of epitopes A and B,and molecular mass of proteins was too small to induce the production of effective immune responses.