Our bodies are a battleground--constantly fighting off infection and disease. But what happens when our bodies fight off something that's helpful, like an artificial knee? It's not good. Now scientists may have discovered a clever fix to this dangerous problem.

"Penn Researchers Develop Protein 'Passport' That Helps Nanoparticles Get Past Immune System"
"The body's immune system exists to identify and destroy foreign objects, whether they are bacteria, viruses, flecks of dirt or splinters."

"Minimal "Self" Peptides That Inhibit Phagocytic Clearance and Enhance Delivery of Nanoparticles"
Foreign particles and cells are cleared from the body by phagocytes that must also recognize and avoid clearance of "self" cells.

"Protein 'passport' helps nanoparticles get past immune system"
Macrophages are immune cell 'border guards' that have evolved to eat all sorts of foreign microbes, but they also eat many particles that are intended for therapeutics and imaging.

"We are constantly being exposed to infectious agents and yet, in most cases, we are able to resist these infections. It is our immune system that enables us to resist infections."

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