Nanoparticles as Vaccines

Today, there are several vaccines that people get routinely; small pox, yellow fever, bacterial meningitis, and the flu vaccine are just a few that have marked, in most cases, the widespread elimination of some of the world's most devastating diseases. While they are extremely effective, it is not entirely known why the vaccines work for as long as they do.
Specifically, the yellow fever vaccine protects someone from yellow fever for up to 10 years. While it is not required at birth, it is necessary for people traveling to South America and Africa. After that time period, a booster is needed to maintain its effectiveness. But researchers at Emory University believed that vaccines work by constantly stimulating Toll-like receptors (TLRs) in the immune system. TLRs are molecules in the immune system that sense minute amounts of viruses or bacteria in the immune system, and thereby stimulate the body's defense system.
With this idea in mind, the researchers created nanoparticles that will continuously stimulate the TLRs in the body, thereby keeping the immune system strong and fighting against yellow fever. They are made of the same synthetic polymer that is used for sutures and grafts, and they have shown great progress in in vivo studies in rats.


Sources
Article: http://www.biologynews.net/archives/2011/02/23/virusmimicking_nanoparticles_can_stimulate_long_lasting_immunity.html
http://www.cdc.gov/ncidod/dvbid/yellowfever/vaccine/index.html