转基因玉米表达的猪传染性胃肠炎病毒纤突蛋白免疫原性鉴定

Identification of the Immunogenicity of Swine Transmissible Gastroenteritis Virus Spike Protein Expressed in Transgenic Maize

为鉴定猪传染性胃肠炎病毒纤突蛋白(TGEV-S)在转基因玉米中的表达及对试验小鼠的免疫原性,本试验在前期TGEV-S转基因玉米植株构建成功的基础上,自玉米叶片中抽提可溶性蛋白作为包被抗原,建立筛选表达TGEV-S转基因玉米的间接ELISA检测方法。结果显示在92份被检测植株中8株为阳性,取阳性值较高的2株152-3和156-6,提取叶片可溶性蛋白,与弗氏佐剂乳化后皮下注射免疫小鼠,只有植株156-6中可溶性蛋白免疫小鼠可产生针对TGEV的抗体,而152-3免疫组检测结果为阴性。利用156-6植株叶片对小鼠进行灌胃免疫,也可产生针对TGEV的特异性抗体。以上结果表明,获得的TGEV-S转基因玉米植株不但可表达TGEV-S蛋白,而且该蛋白通过注射或口服途径免疫小鼠后均可产生针对TGEV-S的特异性抗体,提示TGEV-S转基因玉米具有发展成为TGEV口服疫苗的潜力。

In this study, the spike protein of swine transmissible gastroenteritis virus （TGEV-S） was expressed in transgenic maize and its immunogenicity was identified in mice. Based on the construction of transgenic maize containing TGEV-S, soluble proteins extracted from maize leaves were used as the coating antigen and an indirect enzyme-linked immunosorbent assay （ELISA） was established to detect the expression of TGEV-S transgenic corn. Total 8 transgenic lines out of 92 samples were positive by indirect ELISA. The leaf extracts of two lines 152-3 and 156-6 with the higher positive value were emulsified with Freund＇s adjuvant respectively, mice were immunized by subcutaneous injection route. The serum antibody against TGEV was detected only in 156-6 immunized group. Further, the leaf extracts of line 156-6 was fed directly to mice for oral immunization. The immunized mice developed specific serum antibody against TGEV comparing with the non-transgenic maize group. These studies demonstrated that the TGEV-S polypeptide was not only expressed in transgenic maize but also induced specific antibod- y against TGEV in mice both of injection or oral immunization, indicating the potentiality of transgenic maize used as a source of plant-derived antigen for oral vaccine.