New Emerging Approaches in Vaccine Development

1.  DNA Vaccines

With DNA vaccines, the subject is not injected with the antigen but with DNA encoding the (protein) antigen. The DNA is incorporated in a plasmid, which is then injected into a muscle just as conventional vaccines are:

§    The plasmid is taken up by cells.

§    The gene encoding the antigen is transcribed and         translated.

§    Fragments of the protein are degraded into peptides.

§    These are exposed at the cell surface nestled in class one histo-compatibility molecules where they serve as a powerful stimulant for the development of cell - mediated immunity.

So far, most of the work on DNA vaccines has been done in mice where they have proved to protect them against tuberculosis and other intracellular pathogens. Some experimental work has even been done in humans using a DNA vaccine encoding one of the surface antigens of Plasmodium falciparum, the cause of one of the most serious forms of malaria. 

2. Reverse Vaccinology: A Genome Based     Approach To Vaccine Development 

The conventional approach to vaccine development requires cultivation of the pathogenic microorganism and its dissection using biochemical, immunological, and microbiological methods in order to identify the components important for immunity. This method, while successful in many cases, failed to provide a solution for many of those pathogens for which a vaccine is not yet available. Today, the possibility of using genomic information allows us to study vaccine development in silico, without the need of cultivating the pathogen. This approach, which we have named ‘reverse vaccinology’, reduces the time required for the identification of candidate vaccines and provides new solutions for those vaccines which have been difficult or impossible to develop.