Wolf's discovery demonstrating that a reporter gene is expressed in myocytes subsequent to injection of naked DNA, was exploited by immunologists and vaccinologists to develop a new generation of vaccines. This observation galvanized the research and in a short lapse of time, an oceanic volume of knowledge has been accumulated. The research carried out in a variety of animal models showed the efficacy of genetic immunization against viruses, bacteria, and some parasites by the ability to induce a strong priming effect resulting from long-lasting persistence of plasmid as episomes....