Embodiments of a novel system for delivering an expression vector encoding an antigen to a subject that allows for spatiotemporal control over stimulation of the subjects immune response to the antigen are provided. In some embodiments, the expression vector delivery system includes a polymer linked to an adjuvant in prodrug form that can form polymer nanoparticles and enter a cell (such as an immune cell) under physiological conditions. In some embodiments, the adjuvant is linked to the polymer by an enzyme degradable labile bond, the cleavage of which activates the adjuvant to stimulate an immune response.
