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 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 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.