Protection against cystic echinococcosis in sheep using an Escherichia coli-expressed recombinant antigen (EG95) as a bacterin

The EG95 recombinant vaccine is protective against cystic echinococcus in animal intermediate hosts. Preparation of the existing, registered EG95 vaccines involves semi-purification of the vaccine protein, adding to the cost of production. Truncation of the EG95 cDNA, shortening both the amino and carboxy-termini of the protein, leads to high levels of recombinant protein expression. The recombinant EG95 protein was prepared as a bacterin from clarified, whole bacterial lysate, and used in a vaccine trial in sheep against an experimental challenge infection with Echinococcus granulosus eggs. The EG95 bacterin was found to induce 98% protection. Use of this in a new generation EG95 vaccine would simplify production, facilitate new sources of the vaccine and potentially enhance uptake of vaccination in control of E. granulosus transmission.