Preparation of Chitosan Based Botulinum Neurotoxin E Recombinant Nanovaccine and Evaluation of its Immunogenicity as Oral & Intradermal Route in Mice

Botulism syndrome is caused by one of the seven botulinum neurotoxins. The toxins binding domain have immunogenicity effect and can be used as a recombinant vaccine candidate against botulism disease. Due to the low immunogenicity of recombinant protein, the use of an appropriate vehicle for antigen delivery to target cells is inevitable. The purpose of this study was to evaluate the use of chitosan nanoparticles as carriers for oral and injection administration of Botulinum Neurotoxin Type E (BoNT/E(binding domain recombinant protein. In this experimental study Chitosan nanoparticles containing BoNT/E binding domain recombinant protein were prepared by ionic gelation method and were administered orally and subcutaneously into 5 groups of mice. IgG anti-BoNT/E binding domain titers were assayed by ELISA. Finally all groups were challenged with active botulinum neurotoxin type E and data were analyzed by t-test.In all groups after each administration, the amount of IgG anti-BoNT/E increased. Chitosan nanoparticles did not show a significant increase in the production of IgG anti-BoNT/E binding domain (p>0.05). There was not a significant difference in IgG anti-BoNT/E titre of the mice immunized with nanoparticles containing antigens in the oral and intradermal route (p>0.05). The challenge with active neurotoxin botulinum type E showed that the mice immunized orally, can tolerate 500 folds LD50.The results of this study showed that the recombinant protein of BoNT/E is able to be absorbed through the digestive system and induce an effective immune response. The challenge of immunized mice with active botulinum neurotoxin type E created immune response in oral administration was effective but it was ineffective in injection administration.