A recombinant vaccine against hydatidosis:: production of the antigen in Escherichia coli

A commercial process was developed for producing a recombinant vaccine against hydatidosts in farm animals. The vaccine antigen consisting of a surface protein of the oncospheres of the hydatid worm (Echinococcus granulosus), was produced as inclusion bodies in Escherichia coli. Fed-batch Cultures of E. coli using Terrific broth in stirred bioreactors at 37 degrees C, pH 7.0, and a dissolved oxygen level of 30% of air saturation produced the highest volumetric concentrations of the final solubilized antigen. An exponential feeding strategy proved distinctly Superior to feeding based on pH-stat and DO-stat methods. The plasmid coding for the antigen was induced with isopropyl-beta-D-thlogalactopyranoside (IPTG) at 4 h after initiation of the culture. The minimum IPTG concentration for full induction was 0.1 mM.