Refolding of antigens synthesized as inclusion bodies in Escherichia coli for vaccine preparation

Abstract

Targeting immune responses to antigens that have been shown to be able of promoting protective immune responses may be a promising alternative for the development of safe and effective vaccines. Generally the presence of domains containing antigenic epitopes with the native conformation is important for the generation of neutralizing antibodies. For this reason, there is the need for the production of heterologous recombinant proteins that maintain the preserved conformational properties of the pathogen molecules, and therefore, for the development of efficient refolding processes in those cases that the proteins are produced as inclusion bodies (IB). Expression of heterologous proteins in E. coli is generally quite high, but often it results in their accumulation in IB inside the bacterial cytoplasm. The difficulty of achieving reproductive refolding processes from these aggregates is a serious problem that needs to be resolved for obtaining soluble and immunologically active proteins. The application of high pressure technology (HPT) induces dissociation of protein aggregates, while maintaining the secondary and tertiary structures typical of the native proteins, structures that are usually present in also the IB. This facilitates the subsequent refolding, in opposition to the traditional process of solubilization of IB in the presence of high concentrations of denaturing reagents.Our research group has experience in the use of TPA for the refolding of recombinant proteins from CI. In this project we are proposing to apply HPT in order to obtain the refolding of the recombinant proteins of dengue virus, of Leptospira interrogans and of Schistosoma mansoni from E. coli IB to be used as antigens for the generation of antibodies with affinity for the conformational epitopes that are present in the respective native proteins. (AU)