title: Expression, Purification and Preliminary Clinical Use of Recombinant HBsAg GST-PreS1(21--47 aa) Fusion Proteins.
abstract: Expression plasmids pGEXSI and pGEXSII containing one copy and two orderly joined copies of PreS1(21--47 aa) DNA fragment, respectively, were constructed. GST-PreS1(21--47 aa) and GST-2xPreS1(21--47 aa) fusion proteins were highly expressed in E.Coli TG1, induced by IPTG. The expression level of GST-PreS1(21--47 aa) was about 30% of total soluble proteins in the lysate of expression bacteria, and GST-2xPreS1(21--47 aa) was about 15% of total soluble proteins, asestimated by SDS-PAGE. 50 mg GST-PreS1(21--47 aa) or 20 mg GST-2xPreS1(21--47 aa) with purity over 90% was obtained, respectively, from 1 L culture by using affinity chromatography of glutathione-Sepharose 4B. Direct ELISA results showed that antigenicity of GST-2xPreS1(21--47 aa) was better than GST-PreS1(21--47 aa) and synthetic peptide. Using GST-2xPreS1(21--47 aa) as coated antigen, a sensitive indirect ELISA for detection of anti-PreS1(21--47 aa) antibody, based on protein A-biotin and streptavidin-HRP, was established. The results from 99 sera samples of hepatitis B patients showed that anti-PreS1(21--47 aa) antibody was detected in nearly half of acute hepatitis B patients during recovery, but it was detected only in a few chronic hepatitis patients. Clinical follow-up study suggested that appearance of anti-PreS1(21--47 aa) was related to the course of the disease and recovery of patients. Detection system established in the study is promising for clinical application.
authors.affiliation: Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences, Shanghai 200031, China. zhangzc@sunm.shcnc.ac.cn
authors.forename: Jun
authors.initials: J
authors.lastname: Wei
authors.forename: Xiao-Jin
authors.initials: XJ
authors.lastname: Liu
authors.forename: Guang-Di
authors.initials: GD
authors.lastname: Li
authors.forename: Yuan
authors.initials: Y
authors.lastname: Wang
authors.forename: Zu-Chuan
authors.initials: ZC
authors.lastname: Zhang
authors.forename: Yu-Qin
authors.initials: YQ
authors.lastname: Wang
authors.forename: Zhi-Meng
authors.initials: ZM
authors.lastname: Lu