By Will Soutter
Novel drug delivery is one of the most-researched areas of nanomedicine - now MIT researchers are advancing the field even further with a nanoparticle aerosol spray that could be used to deliver vaccines or cancer treatments via an inhalable spray.
The new lipid nanoparticle vaccine-delivery system could help to make effective vaccine formulations for a wide range of infectious diseases, and even give a boost to the development of cancer vaccines. Image credit: Photos.com.
The new vaccine delivery platform is primarily targeted at vaccines for infectious diseases which attack mucosal membranes in humans - this includes many viral infections like influenza, HIV, herpes simplex, and HPV - along with many other respiratory and sexually transmitted diseases.
Whilst vaccines for many of these infections exist, they are often not very effective, as the mucosal membrane flushes the vaccine antigens away before the immune cells in the area can deliver them to the T-cells - the part of the immune system which forms memories of harmful bodies, to allow the body to rapidly fight off the infection in the future.
Because of these difficulties, very few mucosal vaccines have every been approved for use in humans - those that are used include cholera, rotavirus, typhoid, and a nasally-administered flu vaccine, as well as the well-known Sabin vaccine for polio.
The MIT research group, led by Prof. Darrell Irvine, has developed a solution to this issue by wrapping the vaccine antigens in cross-linked layers of lipids to form nanoparticles. These particles are much more durable than the proteins that make up the vaccine, and allow the vaccine to remain on the membrane for long enough to trigger an effective immune response.
“It’s like going from a soap bubble to a rubber tire. You have something that’s chemically much more resistant to disassembly"
Prof. Darrell Irvine
So far, the vaccine delivery platform has only been tested in mice, with great success. However, infections like HIV do not affect mice, so the studies were carried out with engineered viruses designed to mimic their behaviour in humans.
The researchers also developed a model to test for the nanoparticles ability to deliver cancer vaccines.
Cancer vaccines are a potential novel treatment method where the body's immune system is made to recognize and attack malignant cells.
This would create a very powerful treatment for cancer if successful - unfortunately, thus far the vaccines have suffered from the same issues as the other mucosal infection vaccines.
Irvine's team implanted mice with engineered melanomas designed to produce ovalbumin - a natural protein found in egg whites.
They then vaccinated the mice with ovalbumin, either in its unprotected form or in their lipid nanoparticle system.
The mice that received the nanoparticle vaccine completely rejected the tumours, suffering no serious side effects except for slight weight loss, which they later recovered from.
This is only a simple tumour model, and Irvine is keen to continue the work with more challenging studies. These initial results are extremely promising, however. The nanoparticle vaccine platform has been patented by the researchers, and licensed to Vedantra Pharmaceuticals for further development of the technology for use in both therapeutic and preventative vaccines.