Abstract: According to the sequence of Eg95 gene published on GenBank, primers were designed from a segment about 348 bp sequences encoding highly hydrophilic dominate epitopes, designating as Eg95s. Three repeats of EG95s were obtained by isoschizomer construction method. Three Eg95s were cloned into two expression vectors, pGEX-6p-1 and pET-32a, then transformed into three host bacterias, Escherichia coli BL21 (DE3), Rosseta (DE3) and origami (DE3) for expression, respectively. The expression products were identified by Western blotting, the expression systems were optimizated by detecting the expression level, solubility of the products and their purify methods. The results showed that the best quality of three EG95s was obtained in the expression system of pET-32a and Rosseta (DE3). The Eg95s fusion protein highly expressed by the optimized expression system was with good solubility, and easy to purify, which is benefit for the further preparation of Echinococcus granulosus gene engineering vaccine on a large scale.

Key words: Eg95s; tandem expression; expression system; optimization