| In order to enhance the immunological effect of mucosal vaccine, the gene of bovine IL-6 was cloned, and predicted its reactivity on rat. IL-6 was inserted into eukaryotic expression plasmid PcDNA3.1 (+) located either before or in the gene P12A and 3C as adjuvant, recombinant plasmid Pc-P12A3C,Pc-IL2AP12A3C,pc-P12AIL3C were constructed. Subsequently, sandwich-ELISA, indirect immunoflurescent assay were used to detected the FMDV structure protein expressed in vitro, and FMDV capisid was observed by SEM.Aerosol transmission of foot and mouth disease virus (FMDV) is believed to be an important route of infection, mucosal immunity establishes defence against FMDV entering the body via mucosal surfaces. Therefore, developing the mucosal vaccine provide new concept and possibility.In order to delivery the DNA vaccine to nasal and lower resparatory tract, and improve the residence time, the chitosan coated PLGA nano/micro sphere were made by Emulsion-Diffusion-Evaporation technique, and freeze-dried into powder. In addition, the affect of chitosan concentration, pH on the asorbence of plasmid was studied, the asorbence of plasmid improved when chitosan concentration increased and pH decreased.Guinea pigs were intranasally vaccinated the microparticles containing chitosan coated PLGA nanospheres loaded FMDV DNA vaccine, FMDV specific antibody in serum, FMDV specific IgA in nasal washing were detected, and animal challenge experiments were performed. The results shows that pc-P12AIL3C,pc-P12A3C and pc-IL2AP12A3C induced FMDV specific IgG,IgA in guinea pigs, and the antibody titer decreased systematically. The percent of animal protected against FMDV challenge immunized with pc-P12AIL3C,pc-P12A3C and pc-IL2AP12A3C were 1/5,0/5 and 3/5 respectively. Therefore, the results show the mucosal immune response against FMDV were enhanced through the bovine IL-6 as mucosal molecular adjuvant and chitosan coated PLGA nano/micro spheres loaded the DNA vaccine.
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