Antibody production may take more than 2 weeks, antibodies against DNA are not even that common I would say. I think that's easier that the DNA is digested or degraded. But anyhow, you could try detecting  inflammatory cytokines like IL-1, IL-6, IL-8 in the blood, or you can try checking for any change in leukocytes populations in blood. If a immune response is caused by your immunisation you should find an increase in activated lymphocytes, which are usually in low number. I don't think you will easily notice an increase in leukocytes of the innate immunity, since they are far more abundant.

Typically you would look for Abs against the epitpope encoded by the DNA. usually OVA or such. if you work in short terms experiments you can try a Tetramer stainings for detection of increase in the amount of Ag specific T cells.

however peripheral vaccine won't necessarily induce systemic response in that case you will need to extract the immune cells from the vaccination site.

I attach a good paper about naked  DNA vaccine 

good luck

http://www.jimmunol.org/content/185/6/3463.long  

Depending on what you are vaccinating for and if you have appropriate numbers of mice; you may want to challenge with live pathogen to see if the animals respond, i.e. disease development as well as antibody production.  Sometimes DNA vaccines don't generate strong antibody responses initially.  Also they tend to require multiple boosts after primary immunization.  Good luck.

Hello Raheleh, 

If your DNA (supposing is a CpG DNA) stimulates the animals immune response it might activate TLR9, and therefore you could measure the cytokine response such as IL-1b, TNF, etc by ELISA. If you are doing Plasmid vaccination with a DNA vaccine, maybe the vaccination protocol needs to be modified, here is some reference that you may be interested in. 

http://www.ncbi.nlm.nih.gov/pubmed/23196205

Maybe if you could describe a little more of the specifics of the experiment our comments would be more helpful. 

best regards

Thank you all for your kind responds. Good Luck