A comparison between adjuvant and delivering functions of iron oxide and calcium phosphate nanoparticles, using a model protein against Brucella melitensis

Abstract

Purpose: Calcium phosphate (CaP) and iron oxide (IO) nanoparticles (NPs) are promising adjuvants and delivery systems for vaccination. Furthermore, it has been shown that the chimeric antigen TF/Bp26/Omp31 (TBO) is a good candidate for stimulating protection against virulent Brucella melitensis. Our aim in the present study was to compare the roles of CaP and IO NPs for induction of the immune response and protection against B. melitensis 16M by using the TBO antigen as a model protein. Materials and Methods: The tbo gene was expressed in the bacterial host and was evaluated by SDS-PAGE and western blot. The recombinant TBO was loaded onto CaP (CaP/ TBO) and IO (IO/TBO) NPs. CaP/TBO and IO/TBO NPs were administered subcutaneously. Results: Antibody levels showed that immunization with both CaP/TBO and IO/TBO NPs stimulated mixed Th1-Th2 immune responses. In addition, immunized mice were challenged with a virulent strain of B. melitensis 16M. Immunized mice with CaP/TBO NPs showed a higher degree of protection than vaccinated animals with IO/TBO NPs. Conclusion: Altogether, our results indicated that the CaP NPs are a potent adjuvant and delivery system for subcutaneously administered Brucella antigens.