Many bacterial and viruses infect humans though mucosal surfaces such as the lungs, but often these surfaces clear the vaccine away before it can trigger the desired immune response. Therefore, scientists have been working towards a vaccine that will stick around at the mucosal surfaces for a little longer.
Now researchers at the Massachusetts Institute of Technology (MIT) say they may have made such a breakthrough, developing a nanoparticle vaccine that can generate strong immune responses against mucosal pathogens not only in the lungs but also in the gastrointestinal and reproductive tracts. What's more, the theory could also be applied to cancer vaccines. They tested their construct in mice, finding that it could help contain an engineered HIV virus and prevent it escaping the lungs.
Reporting in Science Translational Medicine, the MIT team beefed up a nanoparticle they had developed two years previously. They made the protein fragments of the vaccine more durable inside the body by encasing them in lipid spheres – calling these â€˜interbilayer-crosslinked multilamellar vesicles' (ICMVs)’. “It’s like going from a soap bubble to a rubber tire. You have something that’s chemically much more resistant to disassembly,” said Darrell Irvine, leader of the research team.
With the particles more resistant to degradation, they remain in the lungs long enough to promote T cell responses. Mice receiving the nanoparticle vaccine fully recovered after infection with a vaccinia virus engineered to produce HIV protein, while the virus was 100% lethal to those who received the non-nanoparticle vaccine. "Giving the vaccine at the mucosal surface in the nanocapsule form allowed us to completely block that systemic infection,” said Irvine.
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