Designation of chitosan nano-vaccine based on MxiH antigen of Shigella flexneri with increased immunization capacity

Shigella flexneri is a gram-negative pathogen that causes shigellosis in humans and primates. MxiH antigen is known as one of the invasive factors in most Gram-negative bacteria consisting of a needle-like structure in the main backbone of the type 3 secretory system. Recombinant MxiH antigen was produced by E. coli BL21 and purified antigen was loaded into chitosan nanoparticles (CS-MxiH). After 20th and 55th of intranasal vaccinations, the titers of IgG, IgA, IL-4, and IFN-gamma were evaluated. The results indicated the successful synthesis of CS nanoparticles followed by the effective loading of MxiH antigen. The results of animal experiments showed that the intranasal administration of CS-MxiH increased IgG and IgA compared to control groups. Increased levels of IL-4 and IFN-gamma in groups immunized with CS-MxiH are probably due to the activation of plasmacytoid and myeloid cells presenting antigen in nasal epithelial mucosa and stimulating B cells.