Gene-expression Profiles of Dendritic Cells Transfected with Targeted Anti-caries Plasmid

Objectives: Targeting antigens to dendritic cells (DCs) have been demonstrated to be an efficient way to improve the immunogenicity of DNA vaccines. However, the mechanism of the immunoenhancing effect has not been reported. Here we constructed a targeted and a non-targeted anti-caries DNA plasmids and compared the gene expression profiles of DCs treated with the two DNA plasmids for the purpose of revealing the potential mechanism underlying the immunoenhancing effect of the targeted anti-caries DNA plasmid. Methods: The targeted anti-caries DNA plasmid pMGJGLU/GFP and the non-targeted anti-caries DNA plasmid pCDGLU/GFP were constructed respectively. BALB/c mice were immunized with pMGJGLU/GFP or pCDGLU/GFP via the intramuscular or intranasal route and the specific antibody responses in saliva and serum were assessed by ELISA. The cultured dendritic cell line named DC2.4 was transfected with pMGJGLU/GFP or pCDGLU/GFP, then 3 days later the total RNA of the two groups of DCs were extracted and reverse transcripted to cDNA followed by hybridization with Dendritic & antigen-presenting cell gene array and quantitative real-time PCR detection. Results: The targeted anti-caries DNA plasmid pMGJGLU/GFP induced significantly higher serum and salivary antibody responses in mice than the non-targeted anti-caries DNA plasmid pCDGLU/GFP. Compared with pCDGLU/GFP-treated DCs, DCs transfected with pMGJGLU/GFP exhibited 28 upregulated genes and 7 downregulated genes. These genes can be grouped into 5 categories based on their molecular functions: cytokines, chemokines and their receptors; antigen uptake; antigen presentation; cell surface receptors; and signal transductions. Among these genes, chemokines CCL17 and CCL19 showed the greatest expression difference between the two groups. Conclusions: The targeted anti-caries DNA plasmid could enhance both systemic and mucosal immune responses compared with the non-targeted plasmid. The upregulation of CCL17 and CCL19 might greatly contribute to this immunoenhancing effect. This study was supported by National Natural Science Foundation of China (Grant numbers: 30330660 and 30700756).