Construction of a plasmid for expression of foreign epitopes as fusion proteins with subunit B of Escherichia coli heat-labile enterotoxin.

A novel vector (pFS2.2) for high-level expression of fusion polypeptides with the nontoxic subunit B (LT-B) of Escherichia coli heat-labile enterotoxin in Escherichia coli and salmonellae is presented. It carries the complete coding sequence of LT-B under lac promoter control and a universal polylinker site for the in-frame insertion of foreign genes at the LT-B gene 3' end. By using this vector, fusion proteins comprising parts of the human or woodchuck hepatitis B virus surface and nucleocapsid antigens are expressed in E. coli and salmonella.