Immunological experiment on dogs by Rabies virus glycoprotein/ nucleoprotein DNA vaccine and IL-18

To assay the immunological effect of rabies virus glycoprotein and nucleoprotein bivalent DNA vaccine and IL 18 on dogs. The double gene vector pIGN alone or in combination with IL 18 in physiological saline or mixed with span glycerol were used to inoculate dogs in quadriceps. Each dog was injected with a dose of 200μg/mL for two times at 2 weeks intervals. The third booster injection was carried out two weeks later by either the same DNA vaccine or a third dose of human inactivated rabies vaccine. Specific immune response was assayed by titration of specific antibodies, neutralizing antibodies and lymphocyte transformation assay. Results showed that (1) the booster injection stimulated a significant anamnestic response in all groups. However, there was no significant difference between groups although pIGN pIIL18 induced higher cell mediated immunity than those without pIIL18; (2) there was no difference in immunological response between the span glycerol DNA vaccine and the DNA vaccine in physiological saline; (3) high immune response could be swiftly induced by a third dose of concentrated rabies vaccine booster in the group primed twice with DNA vaccine. All these indicated that the bivalent DNA vaccine can be applied to immunize dogs in the form of naked plasmids or in the form of mixture with pIIL18. It was demonstrated that bivalent DNA vaccine has the potential in place of inactivated and attenuated vaccines.