Wednesday, March 2, 2011

Nanoparticles used to Mimic Pathogens

One of the major goals of researchers is to develop a vaccine that fosters lifelong immunity. Many live, attenuated vaccines, such as for smallpox or yellow fever, provide protection for decades; however, researchers are uncertain as to how they induce such long-term protection.

Researchers at the Emory Vaccine Center have designed nanoparticles that resemble viruses in size and immunological composition that has induced lifelong immunity in mice. The particles mimic the immune response stimulated by the yellow fever vaccine. One injection of the yellow fever vaccine, developed in the 1930s by Max Theiler, can provide protection for decades. The researchers believe that the vaccine is so effective because it activates multiple TLRs in the innate immune system. The nanoparticles were synthesized to have molecules that turn on TLRs. They are composed of monophosphoryl lipid A (MLA), a component of bacterial cell walls, imiquimod, a chemical that mimics the effects of viral RNA, and polylactic acid-co-glycolic acid (PLGA), a synthetic polymer used for biodegradable grafts and sutures.  The FDA has approved all of these individual components for use in humans.

Bali Pulendran, PhD, states that these particles can serve many purposes for the study and prevention of infectious disease. First, they can increase the stockpiles of viral-like material that can be used for research when natural stockpiles are low. Second, they have the potential to serve as a model for the development of effective vaccines for diseases that do not have them, such as tuberculosis, HIV, malaria, and dengue. Third, they have the potential to improve current vaccines by increasing the duration of immunity in the patient.

Blue = resting B cells. Red = activated B cells that are being "trained" to produce high-quality antibodies. Green = specialized antibody-producing cells.

-Owen Marecic 

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