Objective:To construct Lactococcus lactis (LL) based EmⅡ/3 vaccine of Echinococcus multilocularis and observe its expression efficiency. Methods:EmⅡ/3 gene was obtained through PCR amplification using the pCD-EmⅡ/3 as a template, the gene was cloned into pMG36e to construct pMG36e-EmⅡ/3 and transformed into Escherichia coli BL21 (DE3) competent cell, the recombinant plasmid was identified by double restriction endonuclease digestion, then was electroporated into LL MG1363 to construct recombinant (r) LL-EmⅡ/3 vaccine. After screening for roxithromycin resistance, the plasmid was extracted for PCR identification, and the expression was identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot. Results:The pMG36e-EmⅡ/3 recombinant plasmid was identified by double restriction endonuclease digestion, and there was an approximately 3 600 bp carrier band and a 1 759 bp EmⅡ/3 gene band. The plasmid extracted from roxithromycin resistant rLL strain was used as a template, and 1 759 bp EmⅡ/3 gene was amplified by PCR; SDS-PAGE demonstrated that the rLL-EmⅡ/3 vaccine could express EmⅡ/3 protein with a relative molecular weight of 66 × 10 3, and the expressed protein accounted for about 20% of the total bacteria protein after 3 days of culture; Western blot showed that the expressed protein could be recognized by mouse serum infected with alveolar hydatid cyst. Conclusion:We have successfully constructed the rLL-EmⅡ/3 vaccine of Echinococcus multilocularis, which expresses Em Ⅱ/3 protein with specific antigenicity.

Objective:To construct a recombinant vaccine of Schistosoma japonicum (Sj) mediated by Enterococcus faecalis (Efs, rEfs-Sj26GST vaccine), and to study the expression of Sj26GST-GST fusion protein in the recombinant vaccine. Methods:The recombinant plasmid pGEX-Sj26GST was transformed into the susceptible strain Efs ATCC47077 by electroporation to construct rEfs-Sj26GST vaccine, and the plasmid was extracted for PCR identification. After induction of expression with isopropyl-beta-D-thiogalactopyranoside (IPTG), the products were analyzed and identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot.Results:After PCR identification, a 676 bp fragment was amplified, which was consistent with the length of Sj26GST amplification fragment. SDS-PAGE analysis showed that the relative molecular mass was 52 × 10 3, which was consistent with the band of Sj26GST-GST fusion protein. Western blot results showed that the Sj26GST-GST fusion protein expressed by rEfs-Sj26GST vaccine could be specifically recognized by the serum of Sj infected patients. Conclusion:The rEfs-Sj26GST vaccine is successfully constructed, and the Sj26GST-GST fusion protein expressed by recombinant vaccine can be specifically recognized by the serum of Sj infected patients.

Objective:To construct a recombinant Efs-EmⅡ/3-Em14-3-3 vaccine against Echinococcus multilocularis (Em) using Enterococcus faecalis (Efs) as a vector, and investigate its antigenicity. Methods:The recombinant plasmid pGEX-EmⅡ/3-Em14-3-3 was transformed into Efs ATCC47077 strain using electroporation method, and the recombinant Efs-EmⅡ/3-Em14-3-3 vaccine was constructed. The plasmid was extracted for PCR amplification and identification. The recombinant Efs-EmⅡ/3-Em14-3-3 vaccine was expressed through isopropyl-β-D-thiogalactoside (IPTG) induction, and the recombinant protein was verified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting, and the proportion of expressed proteins in the total proteins of the bacteria was analyzed by thin layer scanning technology.Results:Using the plasmid extracted from recombinant Efs bacteria as a template, the EmⅡ/3-Em14-3-3 fusion gene with a size of about 2 554 bp could be amplified by PCR. The relative molecular mass ( Mr) of the expressed EmⅡ/3-Em14-3-3 fusion protein was approximately 119 × 10 3 by SDS-PAGE; after 5 h induction by IPTG, the expression level of target protein was high, accounting for about 9% of the total bacterial protein. Western blotting showed that the expressed protein could be recognized by mouse serum infected with alveolar hydatid cyst. Conclusion:The recombinant Efs-EmⅡ/3-Em14-3-3 vaccine is successfully constructed, and the expressed fusion protein shows specific antigenicity.

Objective To construct Lactococcus lactis(LL)-based recombinant LL-Eg95(rLL-Eg95)vaccine for Echinococcus granulosus(Eg)and to examine its expression efficiency.Methods Eg95 gene was obtained by PCR from the template of pCD-Eg95.Then,pMG36e was inserted in the Eg95 gene after double cleaving with restriction endonucleases Xba Ⅰ and Hind Ⅲ to construct recombinant plasmid pMG36e-Eg95,which was transformed into E.coli BL2(DE3)competent cells.The recombinant plasmid was extracted and identified by double restriction endonuclease digestion and was then electroporated into LL MG1363 to construct rLL-Eg95 vaccine.Then,the plamid was extracted and identified by PCR.Results Examination of the recombinant plasmid by double restriction endonuclease digestion showed that the segment was of the expected length.PCR showed that 471 base pairs of Eg95 gene were amplified when the plasmid extracted from roxithromycin-resistant recombinant LL was used as the template.Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)showed that the relative molecular mass of the Eg95 protein expressed was approximately 16.5×103 and that the amount of the expressed protein was 17％of the total bacterial proteins.Western blot findings suggested that the expressed protein could be recognized by mice serum infected with hydatid cyst.Conclusion The rLL-Eg95 vaccine was successfully constructed,expressing Eg95 protein that has specific antigenicity.