Vaccines based on DNA are being developed and the results obatined influenza virus. The strategy of DNA Vaccines is as follows the gene encoding the relevant immunogenic protein is isolated cloned and integrated into a suitable expression vector. This is as introduced into the individual to the immunised. THE gene is ultimately expressed in vaccinated individual and the immunogenic protein is expressed in sufficient invoke both humoral and cell mediated immunities. It may be pointed the various approaches for DNA vaccines are as follows.
(1) injection of pure DNA (2) use of vector adenovirus retrovirused E.coli salmonella typhimurium herpesviruseds for delivery of the gene (3) reimplanation of autologous cells into which the gene has been transferred and gun delivery of plasmid DNA which contains the gene in an expression casette.
In skeletal muscle ladthe injection of pure DNA or RNA leads to the uptake and expression of DNA in the muscle cells when gene encoding an immunogenic protein is so introduced its expression also results in immunizaion of the individuals. This approach has potential for delivery of DNA vaccines. The DNA most likely enters the skeletal muscle cells through transient discontinuties in their plasma lemma produced by stretching of the muscle cells during exercise.
To remove cells from the body of an individual into which the concerned immunogen encoding gene is introduced and expressed. These cells are then ireintroduced into the body of the individual in variety of ways. This approach although more cumbersome has the advantage of enabling control of the modified cells within contaniments.