Enhanced Responses to a Targeted Fusion Anticaries DNA Vaccine in BALB/c Mice

Objectives: Dendritic cells (DCs), which express receptors for cytotoxic T lymphocyte-associated antigen 4 (CTLA4), are potent initiators of the immune responses. Targeting antigen to DCs with CTLA4 may increase the effective dose of antigen and enhance immune responses. The aim of this study is to evaluate the immune responses induced by a CTLA4 targeted fusion anticaries DNA vaccine pGJA-P and compare them with a non-targeted fusion anticaries DNA vaccine pGLUA-P. Methods: Groups of BALB/c mice were immunized with pGJA-P or pGLUA-P via intramuscular or intranasal route. Specific anti-PAc and anti-GTF serum IgG and salivary IgA were assayed by using ELISA. Results: pGJA-P intramuscularly immunized mice could induce significantly higher serum IgG much more quickly than pGLUA-P intramuscularly immunized mice (P<0.01). pGJA-P intranasally immunized mice could induce salivary IgA more quickly than pGLUA-P intranasally immunized mice. pGJA-P delivered intramuscularly could induce effective salivary IgA responses which had no significant difference (P>0.05) with pGJA-P delivered intranasally, while no specific salivary IgA was detected in pGLUA-P intramuscularly immunized mice. Effective serum responses did not drop off significantly with time to the end of the study (experimental day 182). Effective salivary responses sustained to 26 weeks in both pGJA-P and pGLUA-P groups. Conclusion: This study indicates that CTLA4 targeted fusion anti-caries DNA vaccine pGJA-P could speed up and enhance specific systemic and mucosal anti-caries immune responses via both intramuscular and intranasal routes.Supported by NSFC grant 30271416.