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Objective To construct and express the recombinant plasmid pET28α-Sj26GST-Sj32 of Schistosoma japonicum(Sj) in Escherichia coli BL21 (DE3). Methods Total RNA was extracted from Sj adult worms by ultrasound-breaking, Sj26GST and Sj32 antigen gene was respectively amplified by RT-PCR from the total RNA; Sj26GST-Sj32 fusion gene obtained with gene splicing by overlap extension(SOEing) was cloned into prokaryotic expression plasmid pET28α and transformed into Escherichia coli BL2 (DE3) to construct pET28α-Sj26GST-Sj32;BL21 (pET28α-Sj26GST-Sj32) was induced with isopropyl-β-D-thiogalactopyranosid (IPTG), and the expressed products were analyzed and identified by sodium dodecyl sulfate polyacrylamide gel electropheresis (SDS-PAGE)and Western blotting. Results The 1991 bp Sj26GST-Sj32 fusion gene was successfully amplified by gene SOEing and cloned into pET28α by restriction analysis and PCR identification, the recombinant plasmid pET28α-Sj26GST-Sj32 was successfully constructed; the relative molecular mass of the expressed recombinant protein was approximately 69 × 103 by SDS-PAGE, and the amount of the expressed protein was 25% of the total bacterial proteins; the fusion protein could be recognized by sera from rabbits infected with Sj by Western blotting.Conclusions The recombinant plasmid pET28α-Sj26GST-Sj32 is successfully constructed and highly expressed in Escherichia coli in fused form with His-tag, and the expressed fusion protein shows specific antigenicity.
ABSTRACT
Objective To construct and express the recombinant plasmid pET32α-Sj26GST of Schistosoma japonicum(sj)in Escherichia coli(E.coli)B121(DE3).Methods The total RNA was extracted from sj adult worms by ultrasound-breaking,Sj26GST antigen gene was amplified by RT-PCR from the total RNA,then cloned into prokaryotic expression plasmid pET32α(+) and transformed into E.coli B12(DE3)to construct pET32α-Sj26GST;BL21(pET32α-Sj26GST)WaS induced with isopropyl-β-D-thiogalactopyranosid(IPTG),and the expressed products were analyzed and identified by SDS-PAGE and Western blot.Results The 676 bp Sj26GST gene was successfully amplified by RT-PCR and cloned into pET32α(+)by restriction analysis and PCR identification,the recombinant plasmid pET32α-Sj26GST was successfully constructed;the relative molecular mass of the expressed recombinant protein was approximately 49×103 by SDS-PAGE,and the amount of the expressed protein was 24%of the total bacterial proteins;the fusion protein could be recognized by sera from rabbits infected with sj by Western blot.Conclusions The recombinant plasmid pET32α-Sj26GST is successfully constructed and highly expressed in E.coli in fused form with Trx-tag and His-tag,and the expressed fusion protein shows specific antigenicity.
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Objective To dynamically observe the changes of cytokines of splenocytes in mice immunized with recombinant bifidobacteria bifidum (Bb)- Eg95-EgA31 vaccine of Echinococcus grauulosus (Eg). Methods Balb/c mice were vaccinated by 5× 108 colony forming unit(CFU) orally and 5 × 105 CFU intranasally, respectively.Mice were killed on week 0,2,4,6,8,10, 12,14,16, 18 and 20 after immunization, respectively, and spleens were separated for cell culture with the stimulation of EgAg, concanavalin A (ConA) or lipopolysaccharide (LPS). The splenocyte supernatants were collected to determine the levels of interferonγ(IFN-γ), interleukin(IL)-12, tumor necrosis factor α(TNF-o) and IL-l0 using enzyme linked immunosorbent assay(ELISA) with MRS as control. Results In the oral immunization group, the levels of IFN-γ, IL-12, TNF-α and IL-10 showed a significant increase from week 2 to week 8, week 2 to week 8, week 4 and week 6 to week 10 after vaccination, respectively, and reached the highest level on week 4, week 2, week 4 and week 6 after vaccination, respectively;in EgAg stimulation group, the levels of IFN-γ, IL-12, TNF-α and IL-10 were (700.0 ± 115.5), (45.0 ± 5.8), (350.0 ± 57.7), (112.5 ± 14.4)ng/L, respectively, compared with week 0[(35.0 ± 5.8), (12.5 ± 2.9), (190.0 ± 11.6), (25.0 ± 5.8)ng/L, P ＜0.05 or ＜ 0.01] and MRS control group[(37.5 ± 5.0),(13.8 ± 2.5), (195.0 ± 5.8), (27.5 ± 2.9)ng/L, P＜ 0.05or ＜ 0.01]. In the intranasal immunization group, the levels of IFN-γ, IL-12, TNF-α and IL-10 showed an obvious increase from week 2 to week 8, week 2 to week 8, week 2 to week 6 and week 6 to week 16 after vaccination,respectively, and reached the highest level on week 2, week 2, week 4 and week 8 after vaccination, respectively;in EgAg stimulation group, the levels of IFN-γ, IL-12, TNF-α and IL-10 were (700.0 ± 115.5), (55.0 ± 5.8),(275.0 ± 28.9), (140.0 ± 11.6)ng/L, compared with week 0[(35.0 ± 5.8), (12.5 ± 2.9), (190.0 ± 11.6), (25.0 ±5.8)ng/L, P ＜ 0.05 or ＜ 0.01] and MRS control group[(37.5 ± 5.0), (13.8 ± 2.5), (195.0 ± 5.8), (27.5 ± 2.9)ng/L, P ＜ 0.05 or ＜ 0.01]. The cytokine levels in the groups with EgAg, ConA or LPS stimulus were significantly higher than those in the corresponding splenocytes suspension groups(P ＜ 0.05 or ＜ 0.01) , and the cytokine levels in the groups with ConA or LPS stimulus were obviously higher than those in the corresponding groups with EgAg stimulation(P ＜ 0.05 or ＜ 0.01). Conclusion The mixed Th1 and Th2 type response can be induced in mice immunized with the recombinant Bb-Eg95-EgA31 vaccine of Echinococcus granulosus in the early stage of immunization(2 to 6weeks).
ABSTRACT
Objective To construct and identify recombinant Bifutobacteria (rBb)-Eg95 vaccine of Echinococcus granulosus (Eg). Methods The total RNA was extracted from hydatid cyst protoscoleces shattered by ultrasound, Eg95 antigen encoding gene was obtained by reverse transcription-polymerase chain reaction(RT-PCR) from the template of total RNA using the primer designed according to the DNA sequence of Eg95, the gene was cloned into Escherichia coli-Bifutobacteria(E.coli-Bb) shuttle plasmid pGEX-1λT and transformed into E.coli BL2 (DE3) competent cell to construct recombinant plasmid pGEX-Eg95 using BamH Ⅰ and EcoR Ⅰ, the recombinant plasmid was identified by restriction endonuclease digestion, then was electroporated into Bb to construct rBb-Eg95 vaccine, the vaccine was identified by PCR. Results Four hundred and seventy-one bp Eg95 gene was amplified by RT-PCR, the products of restriction endonuclease digestion were the same as expected(471 bp Eg95 gene and 4947 bp pGEX-1λT), 471 bp Eg95 gene fragment was amplified by PCR from the template of pGEX-Eg95 extracted from rBb vaccine. Conclusion rBb-Eg95 vaccine of Eg is successfully constructed, which lays the theoretical foundation for exploitation and utilization of this vaccine.