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Aim:To evaluate the comparative immunogenicity and protective efficacy of the cytotoxic T-lymphocyte.associated antigen 4(CTLA-4)fusion anti-caries DNA vaccines pGJA-P/VAX1,pGJA-P,and non-fusion anti-caries DNA construct pGLUA-P in hamsters.In addition,the ability of CTLA-4 to target pGJA-P/VAX1-encoding antigen to dendritic cells was tested in vitro.Methods:All DNA constructs contain genes encoding the A-P regions of a cell surface protein(PAc) and the glucan binding(GLU) domain of glucosyltransferases(GTFs)of cari-ogenic organism Streptococcus mutans.Human dendritic cells were mixed with the CTLA-4-Ig-GLU-A-P protein expressed by pGJA-P/VAX1-transfected cells and analyzed by flow cytometry.Gnotobiotic hamsters were immunized with anti-caries DNA vaccines by intramuscular injection or intranasal administration.Antibody responses to a representative antigen PAc were assayed by ELlSA,and caries protection was evaluated by Keyes caries scores.Results:A flow cytometric analysis demonstrated that CTLA-4-Ig-GLU-A-P protein was capable of bind-ing to human dendritic cells.pGJA-P/VAX1 and pGJA-P induced significantly higher specific salivary and serum anti-PAc antibody responses than pGLUA-R.Significantly fewet caries lesions were alSO observed in hamsters immunized with pGJA-P/VAX1 and pGJA-p There was no significant difference in the anti-PAC antibody level or caries scores between pGJA-P/VAX1 and pGJA-P-immunized groups.Conclusion:Antigen encoded by CTLA-4 fusion anti-caries DNA vac-cine pGJA-P/VAX1 could specifically bind to human dendritic cells through the interaction of CTLA-4 and B7 molecules.Fusing antigen to CTLA-4 has been proven to greatly enhance the immunogenicity and protective efficacy of anti-caries DNA vaccines.