Preparation of a peptide vaccine against GnRH by a bioprocess system based on asparaginase

GnRH is a promising target in hormone-dependent cancer immunotherapy. In our previous study, we have designed and purified a peptide vaccine GhM (GnRH₃-hinge-MVP) by use of the bioprocess system based on asparaginase. Active immunization with GhM in the presence of CFA/IFA evoked strong humoral response. In this study, the motif NRLLLTG with high affinity to nanoparticle carrier VLP HBcΔ-SBD was fused to the C terminus of GhM to form a new peptide vaccine GhMNR (GnRH₃-hinge-MVP-NRLLLTG). The fusion protein ansB-C-GhMNR was controlled by vigorous T7lac promotor and expressed effectively as inclusion bodies after induction by lactose and then purified by means of cell disruption, washing and cold ethanol fractionation. After hydrolyzed for 72h, GhMNR was liberated from the fusion partner ansB-C and purified by CM52 cation exchange chromatography. These results suggested that the bioprocess system is suitable for large-scale expression and purification of the peptide vaccine GhMNR, and even some other proteins or peptides which may be important for industrial or laboratory purposes.