Current status and future perspectives of DNA vaccine delivery by attenuated intracellular bacteria

Vaccination by intradermal or intramuscular injection of antigen-encoding plasmid-DNA elicits strong cellular and humoral immune responses. Professional antigen presenting cells (APC) seem to induce these responses, making it, therefore, desirable to deliver the plasmid molecules directly to these cells. The exploitation of attenuated intracellular bacteria as DNA delivery vehicles makes the direct targeting of DNA vaccine vectors to professional APC feasible.