BACKGROUND AND OBJECTIVE: Ricin toxin is a heterodimer glycoprotein which, due to its high toxicity, is used as a bioterrorism agent. Immunogenicity studies against ricin are now focused on two subunit vaccine candidates, including RiVax and RVEc. These studies have examined the vaccine candidate immunization as an alone and in combination with adjuvant, however, there is not a published study on the immunogenicity evaluation of the candidate vaccine through the delivery by nanoparticles. The aim of this study was preparation and evaluation of RiVax recombinant vaccine-loading in chitosan nanoparticles.
METHODS: In this experimental study, After transferring the RiVax gene to the bacterium, inducing the expression and purification of the RiVax protein by affinity chromatography column, the RiVax protein was loaded with Ionic Gelation method in chitosan nanoparticles. Then, the properties of nanoparticles including size, morphology, loading percentage and release pattern of RiVax protein from nanoparticles and stability of this protein during acidic loading conditions in nanoparticles by SDS-PAGE were evaluated. Also, Immunization study were performed on 3 mouse groups (n=4/group) by RiVax protein, Nanoparticles containing protein and phosphate buffer.
FINDING: The results of this study showed that the nanoparticles containing protein had a size of 178 nm and a Zeta potential of +27.8 MV and a polydispersity index of 0.193. Also, according to SDS-PAGE results, it was found that the RiVax recombinant protein was denatured during the process of preparing the chitosan nanoparticles.
CONCLUSION: The results of this study showed that the RiVax protein has been unstable in acidic conditions for the production of chitosan nanoparticles and Ionic Gelation method is not suitable for loading this protein in chitosan nanoparticles
