口蹄疫病毒非结构蛋白3A、3B和2C基因的表达及产物纯化与活性检测

目的]口蹄疫病毒(FMDV)非结构蛋白(NSP)3A、3B和2C基因的表达及产物纯化与活性检测.方法]利用原核表达系统表达了FMDV NSP 3A、3B和富含B细胞抗原位点序列的2C蛋白.利用高浓度尿素裂解包涵体,采用稀释法和氧化型、还原型谷胱甘肽系统相结合方法对2C蛋白进行复性.用金属鳌合亲合层析的方法对表达的FMDV NSP 3A、3B和2C进行纯化.采用ELISA方法对比检测了3种纯化蛋白在检测羊血清NSP抗体的效果.结果]检测得知3A和3B为可溶性表达蛋白,2C以包涵体形式表达.通过Western-blot分析,表明纯化后蛋白能与FMDV感染动物血清发生特异性反应.纯化的3A、3B和复性后的2C融合蛋白与3ABC抗原的检测结果具有很高的符合性.结论]该研究为建立鉴别FMDV自然感染动物和灭活疫苗免疫动物的酶联免疫电转移印迹技术(EITB)提供了所需的材料.

Purification and reactivity of Foot-and-Mouth Disease Virus non-structural protein 3A, 3B and 2C expressed in E. coli

OBJECTIVE: To purify and to detect reactivity of non-structural proteins 3A, 3B and 2C expressed in the Escherichia coli. METHODS: FMDV NSP 3A, 3B and 2C containing the major B-cell antigenic sites were expressed in E. coli. We got renatured 2C protein by lysing of isolated inclusion body using high concentration of urea, and then diluted in a buffer system containing oxidized/reduced glutathione. Purified 3A, 3B and 2C were obtained by Ni-NTA His Bind Resin affinity chromatography. The reactivity of three NSPs with sera of different origin was measured using an indirect ELISA and Western-blot. The reactivity of three proteins was compared with 3ABC and 3D by detecting sera of clinically healthy sheep that were collected from epidemic region of Asia I FMD. RESULTS: Proteins 3A and 3B were solubly expressed in bacteria, and 2C was expressed to form inclusion body. All three products could react specifically with sera from FMDV infected animal by western-blot and ELISA. The high coincident rates were observed between 3A, 3B, 2C and 3ABC. CONCLUSION: The results would provide useful materials for establishment of immunoelectro-transfer blot (EITB) diagnostic method, which could be used for differentiation of the FMDV infected animals from the vaccinated animals.