Enhanced efficacy of CTLA-4 fusion anti-caries DNA vaccines in gnotobiotic hamsters.
OBJECTIVE
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 cariogenic 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 ELISA, 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 binding to human dendritic cells. pGJA-P/VAX1 and pGJA-P induced significantly higher specific salivary and serum anti-PAc antibody responses than pGLUA-P. Significantly fewer 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.


CONCLUSIONS
Antigen encoded by CTLA-4 fusion anti-caries DNA vaccine 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.
Zhang
Feng
F
Key Laboratory for Oral Biomedical Engineering of Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
Li
Yu-hong
YH
Fan
Ming-wen
MW
Jia
Rong
R
Xu
Qing-an
QA
Guo
Ji-hua
JH
Yu
Fei
F
Tian
Qi-wei
QW
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D015703:Antigens, CD / Q000276:immunology*; D019556:COS Cells; D060908:CTLA-4 Antigen; D002522:Chlorocebus aethiops; D006224:Cricetinae; D003713:Dendritic Cells / Q000276:immunology; D003731:Dental Caries / Q000517:prevention & control*; D005260:Female; D005856:Germ-Free Life; D006801:Humans; D007114:Immunization; D007071:Immunoglobulin A, Secretory / Q000096:biosynthesis; D008647:Mesocricetus; D011993:Recombinant Fusion Proteins / Q000276:immunology; D022541:Streptococcal Vaccines / Q000276:immunology*; D013295:Streptococcus mutans / Q000276:immunology*; D019444:Vaccines, DNA / Q000276:immunology*
D000907:Antibodies, Bacterial; D015703:Antigens, CD; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; D007071:Immunoglobulin A, Secretory; D011993:Recombinant Fusion Proteins; D022541:Streptococcal Vaccines; D019444:Vaccines, DNA