Researchers from the University of Michigan have developed a vaccine, given as a nasal spray, that stopped or greatly reduced peanut allergy reactions in allergic mice.
While they have a lot of study ahead of them, lead researcher Jessica O’Konek, Ph.D, is cautiously optimistic that this vaccine will work in humans and that, in theory, it should work for almost any food allergen.
“We’re really excited about this,” O’Konek, an investigator with UM’s Mary H. Weiser Food Allergy Center, said of the novel vaccine and the first study just published in the Journal of Allergy and Clinical Immunology.
She tells Allergic Living that, unlike other food allergy treatments in development, this vaccine aims higher than desensitization.
When someone is predisposed to food allergy, they have an immune system that didn’t properly switch from the immature, allergy-prone Th2 mode to the infection-fighting mode known as Th1. Yet in the new study, this vaccine appeared to “reset” or retrain the immune system of allergic mice to tolerate the allergen.
With peanut desensitization such as oral immunotherapy, by comparison, the allergy can return if a person stops taking regular maintenance doses.
What’s also encouraging is the timeline: the mice showed protection against peanut when challenged after only three doses of the spray in monthly intervals. “This is something quite novel, in such a limited amount of time, to be able to switch this immune response to suppress Th2 and induce Th1 mode,” said O’Konek.
The immunotherapy vaccine that she and her colleagues have developed uses a tiny amount of peanut alongside a nano-emulsion of minuscule drops (measured in nanometers) of purified soybean oil, detergent and water that have been mixed together at high speed. O’Konek notes the nano-emulsion, previously developed at UM, has already been through safety clinical trials in people as an adjuvant for a flu vaccine. (As well, the emulsion contains no soy protein, so it would not trigger soy reactions.)
Following the three treatments for the study, which received funding from FARE (Food Allergy Research & Education) and the U.S. Department of Defense, the researchers tested the mice. They were given either an oral food challenge or injected with a peanut substance.
With the oral challenge, “we almost completely protected the mice,” says O’Konek. Only a couple of mice had some itchiness, but they had none of the breathing problems seen in allergic mice who got a placebo. With the challenge through injection, “we found that about half the mice didn’t react at all, and the other half still reacted, but were much less severe than the mice that received placebo.” In addition to suppressing immune response, O’Konek says the vaccine also appears to prevent the activation of cells involved in allergic reactions.
If further animal studies are successful, the researchers hope to be able to move to a human clinical trial in about five years. O’Konek said the next priorities are to look at how well the vaccine’s protection against peanut allergy endures, plus they are experimenting with other food allergies – currently they’re testing mice sensitized to either milk or egg.
There is still more work to be done understand the mechanism – which allows this vaccine, when delivered through cells of the nose, to alter the immune system’s response.
FARE’s senior vice president for research and international operations notes the importance of new therapies for food allergy, a disease that now affects 15 million Americans. “Emergency care for severe allergic reactions has increased almost 400 percent during the past decade,” said Mary Jane Marchisotto in a press release. “Effective treatments are urgently needed.”
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