What Is A DNA Vaccine?
DNA vaccines are third-generation vaccines that include the use of engineered DNA plasmids. Here, the Deoxyribonucleic acid or DNA is engineered in such a way that upon administration in the body, it induces both a humoral and cell-mediated immune response against the specific antigen (pathogen) such as virus, bacteria and parasites, along with showing significant stability, producibility and storage.
Many studies say that among the other technologies available for the development of vaccines, DNA vaccines can be promising among all conventional vaccine types. [2]
The first concept of DNA vaccine was made earlier in 1990 and since then, it has become the fastest-growing vaccine technology and also, one among the important discoveries in the history of vaccinology.
According to the WHO, the DNA vaccines not only contain the engineering DNA, but also other supplementary agents that help the DNA enter the cells, target the specific cells and stimulate and direct the immune response towards the antigens.
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How Do DNA Vaccines Work?
DNA vaccines consist of delivering genes or their fragments, also called DNA plasmids. The engineered gene which is used in DNA vaccines encodes proteins that originated from the antigen. [3]
This approach may help the immune system target that specific antigen by inducing adaptive immune responses to mark and kill them, and prevent the risk of infection the next time.
The vaccine formulation is designed in a way that the plasmids used are translocated to the nucleus of the cells, thus triggering the gene transcription of the antigen (pathogen).
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The gene then gets translated into protein, and then into peptides. These peptides help bind the immune system proteins (histocompatibility complex (MHC) class I or II) involved in recognising the antigen to the T-cells.
To mention, T and B cells are part of the immune system that help identify and kill the pathogens entering the body. T-cells are cells that help identify the antigen and mark them while the B-cells are involved in secreting antibodies specific to the antigen and destroying the pathogen.
Therefore, when DNA vaccines are administered, the plasmids in it go to the target cells where they are decoded, thus allowing the T-cells to mark them accurately and B-cells to produce antibodies against them, so that next time when the actual pathogen enters, the body will have the capability to tackle them in many ways.
Why DNA Vaccines Could Be Better Than Other Vaccine Types
Compared to conventional vaccine types or those made with live-attenuated viruses or viral vectors, DNA vaccines could be better due to the following reasons: [4]
Downsides Of DNA Vaccines
Some of the downsides of DNA vaccines include: