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Nasal Spray Vaccine Shown to Control Peanut Allergies

Peanuts in shell

(USDA.gov)

12 April 2018. A vaccine to protect against peanut allergies, given as a nanoscale droplets suspended in a nasal spray, is shown to prevent allergic reactions in tests with lab mice sensitized to peanuts. Results of the tests and a description of the vaccine developed at University of Michigan in Ann Arbor appear in yesterday’s issue of the Journal of Allergy & Clinical Immunology (paid subscription required).

According to Food Allergy Research and Education, an advocacy group that helped fund the study, allergies to peanuts and other foods are a result of the body’s immune system misinterpreting certain food ingredients as pathogens, and responding by the release of histamines, chemicals in the body causing the allergy symptoms. In most cases, the symptoms are mild, such as runny nose and itching, but people with peanut allergies face a real and elevated risk of anaphylaxis, a life-threatening condition constricting airways, swelling the throat, and causing a sharp drop in blood pressure. The group says says some 15 million people in the U.S. including nearly 6 million children, have a food allergy, with growing numbers of people reporting an allergy.

The Michigan team led by pharmacologist Jessica O’Konek and immunologist James Baker are seeking better tools for physicians and their patients deal with food allergies, such as peanuts. “Right now,” says O’Konek in a university statement, “the only FDA-approved way to address food allergy is to avoid the food or suppress allergic reactions after they have already started. Our goal is to use immunotherapy to change the immune system’s response by developing a therapeutic vaccine for food allergies.”

The researchers’ immunotherapy approach harnesses the immune system to prevent the reactions to peanuts caused by the immune system. In this case, the vaccine generates antibodies to block production of cytokines, proteins released by T-cells, white blood cells in the immune system that result in inflammation. At the same time, the vaccine must also activate other T-cells that help regulate immune responses.

The team knew from previous work that mucous membranes in the nose offer a rich target for generating these responses. To activate antibodies in the mucous membranes, the researchers formulated their vaccine into nanoscale droplets, suspended in an emulsion of purified soybean oil. The droplets, say the researchers measure 350 to 400 nanometers, where 1 nanometer equals 1 billionth of a meter. The soybean oil needed thorough purification to retain its physical properties, but also remove possible soy allergens.

The researchers tested the vaccine in lab mice chemically induced with peanut sensitivities. Over a 2 month period, the mice were each given 3 doses of the nasal spray vaccine, either as a nanoscale emulsion, or mixed with a saline solution for comparison, and then given peanuts as food. Mice given the nano-emulsion vaccine show decreases in the allergy-causing cytokines and other proteins before being given peanuts. After feeding on peanuts, the nano-emulsion vaccine recipients show measurable reductions in hypersensitivity and produce more protective interleukin-10 cytokines and T-cells that help regulate immune responses. Mice without the nano-emulsion, on the other hand, exhibit allergic responses, including itchiness and puffy eyes, and in some cases more severe reactions, such as shock.

The team now plans to delve more into the mechanisms for suppressing food allergies and extending the protection time for the vaccine. Baker, who is CEO and medical director of Food Allergy Research and Education, and O’Konek are listed as co-inventors on a patent application for the processes. Baker is also founder of the company NanoBio Corp. in Ann Arbor that licenses the technology.

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