Prokaryotic expression and purification of human Smith D1 antigen / 中华检验医学杂志

ABSTRACT

Objective To obtain recombinant human Smith D1 (Sm D1) antigen and establish detecting assay.Methods Human Smith D1 antigen was synthesized by PCR using human Leukemic cDNA. The prokaryotic expression vector pGEX-ST-Sm D1 was constructed and transformed into E.coli.BL21 cell.Protein expressed under the induction of IPTG.We established DIGFA for detecting anti-Sm D1 antibodies with purified Sm D1 antigens.Results Sequence and restriction analysis revealed Sm D1 gene was cloned in frame into pGEX-5T,SDS-PAGE profile showed a clear protein band with a relative molecular weight of 39 000 and western blotting indicated that the expressed product specifically reacted to polyclonal anti-human Sm D1 genes.There was no significant difference between DIGFA and IB.The agreement between DIGFA and IB was 91.7% as calculated by Kappa statistical method.The sensitivity and specificity of DIGFA were 100% and 83.3% repectively.Conclusions Human Sm D1 gene is successfully cloned、 expressed and purification.The DIGFA,using purified Sm D1 antigens,is as good as IB,rather simpler, more rapid and reliable assay.