DNA immunizations with the major structural protein VP1 of coxsackievirus B3 (CVB3) have been previously found to protect mice from a lethal challenge with CVB3. The function of this vaccination procedure is mainly based on accelerated antibody induction with an early cytokine expression and increased virus-specific cytotoxic activity of spleen cells causing decreased myocyte destruction and reduced viral replication. Here, we report that the co-expression of the immune-stimulatory interleukin-2 (IL-2) can increase the efficacy of the inoculated DNA vaccine depending on the route of administration and the mouse strain used.