A Trojan Horse for Asthma
New Nanoparticle Technology Could Turn Off Allergies
This article was originally published in the Northwestern University Feinberg School of Medicine News Center.
In an entirely new approach to treating asthma and allergies, a biodegradable nanoparticle acts like a Trojan horse, hiding an allergen in a friendly shell to convince the immune system not to attack it, according to new Northwestern Medicine research. As a result, the allergic reaction in the airways is shut down long term and an asthma attack is prevented.
The research used technology that can be applied to food allergies as well. The nanoparticle is currently being tested in a mouse model of peanut allergy, similar to food allergy in humans.
“The findings represent a novel, safe and effective long-term way to treat and potentially ‘cure’ patients with life-threatening respiratory and food allergies,” said Stephen Miller, PhD, Judy Gugenheim Research Professor of Microbiology-Immunology. “This may eliminate the need for life-long use of medications to treat lung allergy.”
This marks the first time this method for developing tolerance in the immune system has been used in allergic diseases. The approach has been used in autoimmune diseases including multiple sclerosis and celiac disease in previous preclinical Northwestern Medicine research.
The scientists studied asthma allergy in mice, but the technology is progressing to clinical trials in autoimmune disease. The nanoparticle technology is being developed commercially to bring this new approach to patients. A clinical trial using the nanoparticles to treat celiac disease is in development.
“It’s a universal treatment,” Miller said. “Depending on what allergy you want to eliminate, you can load up the nanoparticle with ragweed pollen or a peanut protein.”
When the allergen-loaded nanoparticle is injected into the bloodstream of mice, the immune system sees the particle as harmless debris. Then the nanoparticle and its hidden cargo are consumed by a macrophage, essentially a vacuum-cleaner cell.
“The vacuum-cleaner cell presents the allergen or antigen to the immune system in a way that says, this belongs here,” Miller said. The immune system then shuts down its attack on the allergen, and the immune system is reset to normal.
The allergen, in this case egg protein, was administered into the lungs of mice who had been pretreated to be allergic to the protein and already had antibodies in their blood against it. So when they were re-exposed to it, they responded with an allergic response like asthma. After being treated with the nanoparticle, they no longer had an allergic response to the allergen.
The approach also has a second benefit. It creates a more balanced immune system by increasing the number of regulatory T-cells, immune cells important for recognizing the airway allergens as normal. This method turns off the dangerous Th2 T-cell that causes the allergy and expands the good, calming regulatory T-cells.