Objective:To obtain the prokaryotic expression product for the group 6 allergen of Dermatophagoides farine ( Der f 6) and detect its IgE-binding rates with sera from asthmatic children. Methods: By enzyme digestion of pET28a (+)-Der f 6 with BamHⅠ plus XhoⅠ,the target gene Der f 6 was obtained and linked into the vector pET32a (+) to construct the recombinant plasmid pET32a(+)-Der f 6, which was then transfected into E. coli BL21 cells for expression, induced with isopropyl-β-D-thiogalactoside ( IPTG) ,purified by affinity chromatography and identified by SDS-PAGE,Western blot and AMLDI-TOF,and tested by ELISA for IgE reactivity with sera from asthmatic children. Results:The plasmids pET32a(+)-Der f 6 were constructed,transformed into E. coli BL21 and expressed successfully. SDS-PAGE of the purification product showed a specific band,Western blot showed the successful binding between the purification product and the His-tag in the plasmids,and MALDI-TOF/TOF identified the identical structure to the allergen Der f 6. Using the ELISA method developed with the recombinant proteins as coating antigen,the positive rate was 41. 3% (19/46) in asthmatic children allergic to dust mite. Conclusion: The plasmids pET32a (+)-Der f 6 were constructed successfully,expressed in E. coli BL 21 (DE3). The recombinant fusion protein has a good reactivity with sera from asthmatic children.%目的：：获得尘螨变应原第6组分Der f 6原核表达产物并检测其与尘螨过敏性哮喘患儿血清抗体IgE结合率。方法：酶切质粒pET28a(+)-Der f 6获得目的基因Der f 6,将其与pET32a(+)载体连接成质粒pET32a (+)-Der f 6,转化BL21细菌后,用异丙基硫代半乳糖苷( IPTG)诱导表达,用Ni+离子亲和层析柱纯化表达产物,用十二烷基磺酸钠-聚丙烯酰胺凝胶电泳( SDS-PAGE)、免疫印迹实验( Western blot)和蛋白质串联质谱( MALDI-TOF/TOF)鉴定纯化产物。以纯化获得的产物为包被抗原建立间接ELISA法检测尘螨过敏性哮喘患儿血清抗体反应情况。结果：成功构建了原核表达质粒pET32a (+)-Der f 6,将该质粒转化E. coli BL21诱导表达,亲和层析纯化后,SDS-PAGE显示获得目的蛋白,Western blot验证其能够与载体的组氨酸标签结合,质谱鉴定其Der f 6结构一致。以此产物为包被抗原建立间接ELISA检测尘螨过敏性哮喘患儿血清,阳性率为41.3%(19/46)。结论：成功构建了原核表达质粒pET32a (+)-Der f 6,亲和纯化获得的目的蛋白具有良好的反应原性。
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