A new anti-allergy bullet

Hiding allergens inside nanoparticles may make allergy shots safer and more effective

by Monique Breuyt, The article is published with the approval of Scientific American Israel and the Ort Israel network 25.09.2016

Allergy sufferers usually rush to the pharmacy at the first signs, itchy eyes and runny nose, to relieve themselves with over-the-counter medications. But such drugs only alleviate the allergy symptoms and do not treat the root of the problem: the overreaction of the immune system to harmless substances. The only cure for allergy is a series of injections, each of which contains a small dose of an allergy-inducing substance (allergen) given over months to years to lower the body's level of sensitivity. But many allergy sufferers avoid these injections due to the fear of serious side effects, including hypersensitivity to proteins (Anaphylaxis).

This dilemma led the Stephen Miller from Northwestern University and Lonnie Shea from the University of Michigan for the task of developing a safer method: a method that would briefly hide the contents of allergy shots from attacks by the immune system.

In order to teach the immune system who is the enemy and what is not the enemy, the body must make an acquaintance between the developing cells of the immune system in the liver and spleen and between the harmless proteins that are supposed to leave to their own devices later. The problem is that mature immune cells sometimes attack the injected allergens before they reach these study centers. Miller the immunologist and Shah the biomedical engineer therefore designed a method to inject the allergens while they are hiding in a Trojan horse: a nano-particle. These particles are about the size of dead cell fragments, so the immune system sees them as normal debris and allows them to pass through the bloodstream and reach the liver and spleen. There the shell of the particles dissolves and the allergenic content spills out.

As the researchers published in their new paper in the Proceedings of the National Academy of Sciences (PNAS), they tested the idea in mice allergic toOvalbumin, a protein found in eggs. The researchers loaded nanoparticles with egg proteins, which if injected alone would have triggered an acute allergic reaction, and injected them into five mice. The mice showed no reaction. The researchers then injected pure ovalbumin to see if the mice were still allergic, but they showed no sign of airway inflammation. Moreover, blood tests revealed an increase inSuppressive T cells that suppress the immune system. These results show that the nanoparticles do serve as a cloak of invisibility that allows allergens to evade the body's defense systems as if they were invisible, and then the immune system learns that these allergens do not belong to the "bad guys".

According to Carrie Nadeau, MSean N. Parker Center For allergy and asthma research at Stanford University, the use of nanoparticles in allergy treatments may offer a powerful tool to combat a wide range of allergies and even autoimmune diseases such as multiple sclerosis. This is because it is possible to fill the nanometer shell with stimulators of many different types of substances that stimulate the immune system, including pollen from pollinators and dust mites. Other researchers have already seen positive results in experiments with nanoparticles in the treatment of peanut allergies. Miller and Shea soon plan to conduct a clinical trial for celiac disease, in which the immune system overreacts to proteins found in wheat.