November 6, 2012
DNA Vaccine Technology Paves The Way For Effective, Low Cost Protective Methods
Connie K. Ho for redOrbit.com — Your Universe Online
Researchers from Arizona State University (ASU) recently revealed novel technology that could help protect against a number of pathogens at lower costs and with improved methods.A re-engineered bacterium that can quicken the delivery of the DNA vaccines to host cells, the new platform was found to provide complete protection against influenza in mice. The team of investigators believes that the new technique could be manufactured to defend against almost any infection at low cost and will not bring any risk to individuals who are already vaccinated or to other members of the public.
"The technology that we're describing in this paper can be used to develop a vaccine against any virus, any parasite, any fungus, whereas this was never possible before the development of recombinant attenuated bacterial strains like those produced in our lab," explained Roy Curtiss, director of the Center for Infectious Disease and Vaccinology at ASU, in a prepared statement.
The findings of the study were recently published in the online Early Edition (EE) of the Proceedings of the National Academy of Sciences.
"By delivering the DNA vaccine using a recombinant attenuated bacterium, we can get 10,000-100,000 doses per liter of culture," commented the study´s lead author Wei Kong, a research assistant professor at ASU, in the statement. "This crucial safety feature ensures that Salmonella are unable to persist as living organisms to survive if excreted into the environment.”
In completing this project, the scientists faced a number of challenges. For one, they had to make sure that the live pathogenic strains would not lead to illness or migrate into the environment. They also worked to produce orally administrative vaccines that were safe and effective but at reduced costs. The team of investigators ended up pioneering a new technique using Salmonella to deliver a group of disease antigens to the recipient cell. The scientists were able to develop recombinant attenuated Salmonella vaccines (RASVs) that could initiate a significant, system-wide immune response and provide immunity.
The most recent results of the study involve a universal DNA vaccine delivery vehicle that was changed from a delayed-lysis Salmonella strain. With the DNA vaccine, cellular and humoral immune responses would be stimulated against protein antigens and allow the host cells to produce particular gene products. This would allow antigens to be produced and then undergo hosted cell modification.
"Here, we were able to deliver a vaccine whose DNA sequence induces the immunized individual to make the protective glycoprotein the way you would during a viral infection," continued Curtiss in the statement.
This new orally-administered RASV is considered more effective than previous DNA vaccines that were given via intramuscular injection or gene gun. These past methods were not able to deliver the vaccine to specific internal lymphoid tissues and mucosal tissues. With the increase of influenza around the world, there is an increasing need for vaccines; however, researchers believe that the global capacity is limited and they fear the production of weaponized influenza strains by bioterrorists.
As such, the team of investigators stated that there is a need for new ways to design, manufacture and apply vaccines. The innovative methods will have to be able to quickly produce effective vaccines of influenzas and other possibly deadly pathogens. The researchers note that new DNA vaccine studied at ASU is a step forward in that direction.
"But now we have the opportunity to produce vaccines against such pathogens," concluded Kong in the statement.