Abstract

Plasmids are circular deoxyribonucleic acid (DNA) vectors that can be used as vac- cines to prevent various types of diseases. These plasmids are DNA platforms that are usually composed of a viral promoter gene, a gene coding resistance to antibiotics, a bacterial origin of replication gene and a multiple cloning site (MCS) for a transgenic region, where one or several genes of antigenic interest can be inserted. Immunization with these recombinant vectors allows intracellular expression of the encoded antigens by molecular and cellular machinery of transfected cells, stimulating an antigen-specific immune response. This process provides an effective protection against diverse types of pathogens, tumor cells and even allergy and autoimmune diseases. Protective efficacy is achieved by the induction of a strong humoral and cellular immune response dependent on B and T cells. The immunity induced by these DNA vaccines, added to the ease of production, administration, genetic stability, and safety, has transformed plasmid-based immunization into a safe strategy in prevention of various diseases.