This nanoparticle was built by Irvine and his colleagues two years ago. The protein fragments that make up the vaccine are encased in a sphere made of several layers of lipids that are chemically "stapled" to one another, making the particles more durable inside the body. This allows the particles to resist disintegration once they reach the lungs. With this sturdier packaging, the protein vaccine remains in the lungs long enough for immune cells lining the surface of the lungs to grab them and deliver them to T cells. Activating T cells is a critical step for the immune system to form a memory of the vaccine particles so it will be primed to respond again during an infection.
The particles also hold promise for delivering cancer vaccines, which stimulate the body's own immune system to destroy tumors. To test this, the researchers first implanted the mice with melanoma tumors that were engineered to express ovalbumin, a protein found in egg whites. Three days later, they vaccinated the mice with ovalbumin. They found that mice given the nanoparticle form of the vaccine completely rejected the tumors, while mice given the uncoated vaccine did not.
The MIT scientists keep working on the development of this nanoparticle vaccine in order to use it to cure some other sickness.