中文摘要：

为制备只包含抗体可变区片段（Fv）的MAb2-5G2单链抗体（scFv）,本研究从分泌MAb2-5G2的杂交瘤细胞中提取总RNA,反转录制备cDNA作为模板扩增重链可变区（VH）和轻链可变区（VL）基因。以VH-linker-VL的形式通过重叠PCR制备scFv基因,构建重组表达质粒pEasy-scFv,并在大肠杆菌中获得正确表达。通过western blot和间接免疫荧光鉴定表明scFv蛋白能够被兔抗MAb2-5G2的抗体（Ab3）识别,复性后的scFv蛋白能够特异性结合Marc-145细胞。该研究结果为进一步明确MAb2-5G2结合Marc-145细胞功能区域奠定了物质基础。

英文摘要：

Anti-idiotype plays important roles in the immune responses against porcine reproductive and respiratory syndrome virus（PRRSV）.Our previous study has shown that the monoclonal anti-idiotype antibody（MAb2） 5G2 specific to anti-PRRSV GP5 antibody could recognize and bind to Marc-145 cells.To further understand the functional domain of MAb2-5G2 for binging to Marc-145 cells,the variable light（VL） and variable heavy（VH） chain genes of MAb2-5G2 were amplified from the hybridoma cells secreting MAb2-5G2 by RT-PCR.VL and VH encoding were fused with a linker to form VH-linker-VL by overlapping-PCR.VH-linker-VL was then cloned into pEasy-E1 vector and expressed in E.coli BL21.The results showed that the expressed scFv protein was recognized by the rabbit anti-MAb2-5G2 antibodies（Ab3） by western blot and the refolded scFv protein specifically bound to Marc-145 cells by indirect fluorescence assay.