Sunday, 13 July 2014

Vaccines developed from DNA nanostructures come one step closer to a clinical reality

Vaccination is one of the most effective ways to prevent microbial infection. International vaccination campaigns have played a pivotal role in the eradication of small pox and the imminent eradication of polio. Yet, formulating effective vaccines is more of an art than an exact science. Several widespread and devastating diseases including malaria and HIV are proving difficult to develop vaccines against.


         Traditionally, vaccines were formulated using attenuated or inactivated versions of the microbes they were intended to treat. However, inactivated microbes do not often elicit a strong enough immune response to induce antibody production. Attenuated viruses, on the other hand, may revert back to an active form within the body. There are also inherent difficulties in ensuring batch-to-batch consistency of the formulations. These shortcomings have led to a progressive shift towards the development of synthetic vaccines
Synthetic vaccines can combine a portion of the target microbe, known as an ‘antigen’ together with an adjuvant that stimulates the immune system. They are more reproducible and have the potential to induce consistent and tailored immune responses. Yet, delivering both the adjuvant and antigen together to the appropriate immune cells is challenging.
The emerging field of DNA nanotechnology may provide a solution. On top of acting as a scaffold to co-deliver antigen and adjuvant, DNA nanostructures allow precise modification of the structure and presentation of these components. The design freedom of DNA nanostructures allows a vaccine developer to tailor the interaction of the nanostructure with both the targeted immune cell populations and off-target cells, creating a selective response.
Reporting in the the July 3, 2012 online edition of Nano Letters ("A DNA Nanostructure Platform for Directed Assembly of Synthetic Vaccines"), a team of researchers based at Arizona State University and headed by Yung Chang, PhD and Hao Yan, PhD demonstrated that DNA nanostructures with appended adjuvants could elicit antibody production against a model antigen in mice. Until now, the potential of DNA nanostructures to act as vaccines has only been demonstrated in vitro.

source: nanowerk