Chitosan Nanogel Based Candidate Vaccine against EHEC

Background and Objective: Enterohemorrhagic Escherichia coli (EHEC) can cause diarrhea and hemorrhagic colitis in humans. The attachment of EHEC to intestinal epithelial cells is the first step of infection which the protein Intimin plays a key role in this process. An immunogen consisting of Intimin can inhibit the attachment of EHEC and prevent diarrhea. Encapsulation of antigens in particular carriers such as chitosan nanogels not only protects them from degradation in environmental conditions but also provides the effective concentrations of antigens in targets and increases bioactivity. The aim of this study was the investigation of immunization against EHEC using chitosan nanogels loaded with protein. Materials and Methods: The protein was expressed in E.coli and purified. Chitosan nanogels were prepared by reacting chitosan with tripolyphosphate (TPP) as a crosslinking agent .The nanogels were loaded with Intimin and their structures were characterized by SEM and DLS. Nanogels and solution protein were introduced in Balb/C mice by oral and parenteral routes respectively. Antibody titers were determined by ELISA. Immunized and nonimmunized mice were tested with E.coli O۱۵۷:H۷. Results: Loading efficiency of the nanogels was ۱۰۰% after ۴۸h of incubation. The average particle size was ۲۱۸ nm. Immunization of mice induced serum IgG antibody response. The protection of immunized animals via oral route was better than parenteral route. Conclusion: Chitosan nanogels loaded with Intimin can be used as an effective vaccine against EHEC.

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Keywords: Chitosan nanogel , E.coli O۱۵۷:H۷ , Intimin , Immunogen