Promising peanut allergy vaccine misdirects the immune system

We don't want to sound ungrateful for everything our immune system does for us, but as people suffering from food allergies can attest, it can be a little overzealous at times. Now, researchers at the University of Michigan have found a way to retrain the immune system to ignore allergens by developing a nasal spray that vaccinates against peanut allergies, with promising results in mouse tests. 

The immune system's job is to identify threats to the body and fight them off, but it doesn't always pick the right targets. In some people, the immune system overreacts to the presence of proteins from things like nuts, dairy products, latex, bee stings or certain drugs, leading to allergic reactions that can, in the most extreme cases, be potentially fatal.

"Right now, the only FDA-approved way to address food allergy is to avoid the food or suppress allergic reactions after they have already started," says Jessica O'Konek, lead author of the new study. "Our goal is to use immunotherapy to change the immune system's response by developing a therapeutic vaccine for food allergies."

In a way, developing a vaccine for allergies requires the opposite approach to a vaccine against disease. In the latter case, the goal is to train the immune system to recognize the invaders and mount a more efficient defense next time. Vaccinating against allergens, on the other hand, requires teaching the immune system to ignore these harmless proteins.

In the new study, the team's experimental vaccine works by effectively misdirecting the immune system to fight off a more dangerous target than the allergen. The vaccine, delivered as a nasal spray of very fine droplets, is made up of peanut proteins mixed with nano-emulsion consisting of highly purified soybean oil, detergents and water.