A Targeted DNA Vaccine Protected Gnotobiotic Rats from Dental Caries

Objectives: To observe the expression of a targeted fusion anticaries DNA vaccine pGJA-P in situ. To compare the levels of specific antibodies and anticaries efficacy generated by pGJA-P and pGLUA-P, a non-targeted fusion anticaries DNA vaccine. Methods: pGJA-P was administrated intramuscularly or intranasally to Wistar rats , and the expression of recombinant protein was detected by immunohistochemistry technique. Wistar rats were fed a cariogenic diet and orally infected with S. mutans, then immunized with pGJA-P or pGLUA-P via the intramuscular or intranasal route. All rats received a single booster immunization 2 weeks later. At the termination of the experiment, blood and saliva samples were collected for assay of antibodies by ELISA and jaws were obtained for caries evaluation by the Keyes method. Results: Recombinant protein could be detected in muscle tissue in intramuscularly immunized rats, and in nasal mucosa in intranasally immunized rats. Rats immunized intramuscularly with pGJA-P had significantly higher serum IgG levels than others(P<0.01). Rats immunized intranasally and intramuscularly with pGJA-P had significantly higher salivary IgA levels than others(P<0.01). Keyes scores of pGJA-P groups were significantly lower than those of pGLUA-P groups and control groups(P<0.01). Conclusions: pGJA-P could be correctly expressed in situ. pGJA-P was much more effective than pGLUA-P. Supported by NSFC grant 30271416.