[Construction and expression of the Echinococcus granulosus recombinant BCG-EgG1Y162].

Objective: To construct and express Echinococcus granulosus recombinant bacille Calmette-Guerin (BCG) strain rBCG-EgG1Y162.

Methods: The encoding gene of the antigen EgG1Y162 of E. granulosus was recombined with E. coli-Mycobacterium shuttle expression plasmid vector pMV361 by genetic engineering technique, and transformed into E. coli for amplification. The recombinant plasmid rpMV-EgG1Y162 was identified by PCR, double digestion with restriction enzymes, and sequence analysis. The confirmed rpMV-EgG1Y162 was transformed into BCG strain via electroporation technique to construct the recombinant rBCG-EgG1Y162. After identification by PCR and double digestion with restriction enzymes, the recombinant strain was cultured for about 2 weeks. In order to induce the expression of target protein, the rBCG was placed in 45 degrees C for 30 min. SDS-PAGE and Western blotting were used to analyze the expressive protein.

Results: The product of recombinant plasmid rpMV-EgG1Y162 was approximately 360 bp by PCR amplification and double digestion with restriction enzymes, consistent with the expected fragment length. Sequencing results showed that the inserted sequence was correct. The rBCG-EgG1Y162 grew well and the identification of PCR and enzyme digestion revealed accuracy. The results of SDS-PAGE and Western blotting showed that the relative molecular weight (M(r)) of the protein was about 71 000.

Conclusion: The E. granulosus rBCG-EgG1Y162 strain is constructed and expressed.