Not to be sneezed at: Decorated nanoparticles prevent allergic reactions

Image: — © AFP/File Mohd RASFAN

The new approach prevented anaphylaxis without causing side effects based on a mouse study. This could lead to the first selective therapy to prevent allergic reactions.

Besides avoiding allergens, no methods exist to prevent allergic reactions. This makes everyday life difficult for many people (from itchy hives and watery eyes to trouble breathing). However, it now appears that a form of nanotherapy could provide a solution. The technology works by selectively targeting the immune cells responsible for allergic responses.

With the development from Northwestern University, a nanoparticle is coated with antibodies that engage with and then deactivate specific cells responsible for responding to a specific allergen. The pilot study, therapy prevented anaphylaxis in all mice exposed to an allergen.

This is based on seeking to eliminate mast cells in order to prevent allergic reactions that could be damaging to other useful, healthy responses. Previous studies identified Siglec-6, a unique inhibitory receptor that is highly and selectively found on mast cells. The new research focused on using nanotechnology to target that receptor with an antibody.

To develop the new therapy, the researchers decorated nanoparticles with antibodies capable of shutting down specific immune cells (called mast cells) responsible for allergic responses. The nanoparticle also carries an allergen that corresponds to the patient’s specific allergy.

In terms of how the therapy works, the allergen engages the precise mast cells responsible for the specific allergy, and then the antibodies shut down only those cells. This highly targeted approach enables the therapy to selectively prevent specific allergies without suppressing the entire immune system.

The nanoparticle comprises dynamic polymer chains, which can independently flip their orientation upon exposure to different solvents and proteins. This helps the nanoparticle to better survive the different types of biological processes that will be encountered within the human body.

According to lead scientists Evan A. Scott: “Currently, there are no methods available to specifically target mast cells. All we have are medications like antihistamines to treat symptoms, and those don’t prevent allergies. They counteract effects of histamines after the mast cells already have been activated.”

Scott adds: “If we had a way to inactivate the mast cells that respond to specific allergens, then we could stop dangerous immune responses in severe situations like anaphylaxis as well as less serious responses like seasonal allergies.”

The research has been published in the journal Nature Nanotechnology.  The study is titled “Controlled adsorption of multiple bioactive proteins enables targeted mast cell nanotherapy.”