 |
||
 |
|
|
 |
||
|
Modern vaccines comprise purified, inac- tivated microorganisms typically administered by a sterile if painful injection. Today's vaccines generally introduce a weakened version of an antigen that stim- ulates the production of specific antibodies. In a new and promising approach, DNA vaccination, genes encoding an antigen are delivered to cells that then pro- duce the antigen and display it on their surface. New drive systems are at the heart of the new delivery mechanisms. They can include, among others, genetic vaccination using plasmid DNA, microparticle-based DNA delivery (in which the genes are encapsulated within or immobilized on a spherical polymer particle), and live attenuated transgene vectors. The new delivery mechanisms can im- prove vaccine potency by targeting the genes to appropriate cells of the immune system, and allow for the expression of antigens in synchrony with the life cycle of white blood cells and pathogen life-cycle stages. This approach stimulates a cell-killing immune response (cellular immune response) as well as a humoral immune response. Control of a vaccine delivery mechanism can become crucial in the management of a pathogen virulence trajectory. | |
|
||