Nanoparticles reprogram mouse immune systems to cope with allergens

Two doses of allergen-encapsulating nanoparticles delivered intravenously prevented anaphylaxis during a food allergy test in mice, according to a study led by University of Michigan researchers.

The results, published in Advanced Healthcare Materials, offer a potential path to improving the ease of allergy immunotherapies in humans which currently require daily doses of the allergen. In addition to the research in mice, this allergen-encapsulating nanoparticle platform has completed a Phase II clinical trial for treating the autoimmune condition celiac disease.

Allergen-specific immunotherapies aim to treat food allergies with a daily dose of the food allergen. Over time, patients can become desensitized, yet the allergic response may re-emerge after patients stop taking the allergen daily.

"Rather than focusing on desensitization, treatment with allergen-encapsulating nanoparticles actually retrains the immune system not to react to an allergen – a process termed tolerance," said Lonnie Shea, a Steven A. Goldstein Collegiate Professor of Biomedical Engineering at U-M and co-corresponding author on the study.

At just 500 nanometers in diameter, these particles are 0.5% the width of a human hair and hold a negative surface charge that targets them to immune cells.

"These characteristics of the nanoparticle make them appear like debris from dying cells, which are generally not viewed as dangerous. The encapsulated allergen is processed by the immune cells without upregulating danger signals that would normally activate an immune response," said Shea.

Image source: Shea Laboratory.