Advantages of genetically modified plant vaccines

Compared with traditional vaccines, genetic vaccines have the following significant advantages:

1. Plasmid DNA is very stable, easy to store and transport, and easy to use. And the preparation is simple, easy to mass produce, low cost. For viruses that are toxic and dangerous, as well as vaccines that are difficult to extract antigens, the preparation of gene vaccines is relatively safe and much easier.

2. Plasmid DNA can exist in the host body for a long time, and antigenic genes are continuously expressed in the body to produce antigenic proteins, which constantly stimulate the body's immune system to produce long-term immunity, and the immunization effect is reliable.

3. Gene vaccines can not only generate humoral immune response, but also lead to activation of cytotoxic T-lymphocytes and induce cellular immunity, while only traditional vaccines can induce cellular immunity with live vaccines, but there is a danger of the virulence of live vaccines rising back.

4. The gene vaccine prepared with the conserved DNA sequence of the core protein can generate immune response to all mutant subtypes of pathogens (bacteria or viruses), thus avoiding the problem of immune evasion due to the mutation of pathogens.

5. A plasmid vector can clone multiple antigenic genes to form a multivalent vaccine, so that one gene vaccine can prevent multiple diseases.

6, plasmid DNA is non-immunogenic, and will not induce autoimmune reactions against the vector as recombinant vaccines do, at least no anti-DNA antibodies have been detected. In addition, the gene vaccine will not be affected by the body's existing antibodies. As a new type of vaccine, there are still many issues that need to be further studied:

1. Safety: plasmid DNA is generally not integrated into the genome of the host cell, and no evidence of insertion mutations has been found. However, the possibility of mutations caused by a few plasmid DNA inserted into chromosomes cannot be completely ruled out. Once integrated into the genome it may activate cellular oncogenes or inactivate oncogenes.

2. Protection efficiency: So far, the immunization efficiency of gene vaccines is difficult to achieve 100% immunoprotection, and there are obvious individual differences in species, which may be related to different animal cells require different promoters, antigen genes, drug delivery methods and dosages.

3, immune tolerance: the continuous expression of gene vaccines in vivo to produce antigenic proteins, may break the body's own immune balance, triggering immune tolerance.