DNA vaccination is a technique for protecting against disease by injection with genetically engineered DNA so cells directly produce an antigen, producing a protective immunological response. DNA vaccines have potential advantages over conventional vaccines, including the ability to induce a wider range of immune response types. Several DNA vaccines are available for veterinary use. Currently no DNA vaccines have been approved for human use. Research is investigating the approach for viral, bacterial and parasitic diseases in humans, as well as for several cancers.
DNA vaccines are third generation vaccines. They contain DNA that codes for specific proteins (antigens) from a pathogen. The DNA is injected into the body and taken up by cells, whose normal metabolic processes synthesize proteins based on the genetic code in the plasmid that they have taken up. Because these proteins contain regions of amino acid sequences that are characteristic of bacteria or viruses, they are recognized as foreign and when they are processed by the host cells and displayed on their surface, the immune system is alerted, which then triggers immune responses (Alarcon JB, 1999 and Robinson HL, 2000).
The phrase edible vaccine was first used by Charles Arntzen in 1990 and refers to any foods; typically plants, that produce vitamins, proteins or other nourishment that act as a vaccine against a certain disease (Concha C, 2017). Once the plant, fruit, or plant derived product is ingested orally, it stimulates the immune system (Concha C, 2017). Specifically, it stimulates both the mucosal and humoral immune systems (Mishra N, 2008). Edible vaccines are genetically modified crops that contain added “immunity” for specific diseases (De Silva GO, 2017). Edible vaccines offer many benefits over traditional vaccines, due to their lower manufacturing cost and a lack of negative side effects.