RESUMEN
TSO18 gene was subcloned into the Pichia pastoris expression vector pPIC9K. The recombinant plasmid pPIC9K-TSO18 was transformed into P. pastoris GS115 by electroporation so that the plasmid will be integrated with chromosome of P. pastoris. The P. pastoris strains containing multi-copy recombinant were screened by G418 and induced by methanol. The expression product was analyzed by SDS-PAGE, Western blot, deglycosylation, and purified by Sephadex column, and was used to immunize mice. The results indicated that the target protein was efficiently expressed in P. pastoris, and glycosylated moderately, and had immunological activity. In a 5 liter fermentor, the expression level of the target protein was up to 2.54 mg/mL. These results will benefit for the development of genetically engineering vaccine.