Experimental vaccine prevents dangerous allergic attack for a year

Mice can be protected from the life-threatening allergic reaction anaphylaxis for at least a year using an experimental vaccine. The hope is that this will work in humans too.

The threat of anaphylaxis constantly hangs over hundreds of millions of people around the world. allergy to foods such as peanuts or shellfish is one common risk factor. In the UK, for example, about 6 percent of adults – or 2.4 million people – are He is estimated to have a clinically confirmed food allergy.

Eating contaminated food or even kissing someone who recently ate food that causes a reaction in youcan cause a surge in molecules produced by the immune system called immunoglobulin E (IgE) antibodies, leading to swelling of the tongue or throat, difficulty breathing, and a drop in blood pressure. This may result in a hospital visit, even if you have an epinephrine auto-injector such as an EpiPen on hand to reverse symptoms. In severe cases, anaphylaxis can be fatal.

In addition to trying to avoid the allergen, options to prevent such attacks limited. You can try oral immunotherapywhich involves eating small, gradually increasing amounts of the allergenic food under supervision to build tolerance, or taking a drug called an anti-IgE monoclonal antibody, such as omalizumab, which binds to IgE, preventing it from causing a reaction. But omalizumab is expensive and must be given every few weeks, possibly for life.

Now, Laurent Reber at the Toulouse Institute of Infectious and Inflammatory Diseases, France, and colleagues developed a vaccine called IgE-K. This causes the immune system to produce antibodies that target IgE, preventing it from binding to receptors on immune cells and stopping the subsequent uncontrolled allergic reaction.

“We wanted to find a solution that could be long-term, because if you have a food allergy, you could accidentally become infected at any time, so you really want to be protected at all times,” Reber says.

In tests on mice modified to produce the human version of IgE, the researchers found that two doses of the vaccine caused the mice to produce neutralizing antibodies against IgE.

“It blocks the molecule that causes our allergies,” says Josh Koenig at McMaster University in Ontario, Canada.

The researchers then gave the mice a substance that caused an allergic reaction. Unvaccinated mice had a severe reaction, but vaccinated mice were protected from anaphylaxis for a year without any side effects.

“It could have been longer, but we didn’t test longer,” Reber says.

IgE is part of the body's immune system and not only causes allergic reactions, but is also activated in response to poisons and some intestinal parasites. “It's probably an inherited system that helps fight toxins,” Reber says.

Reber says many people at risk of serious allergic reactions have received anti-IgE therapy for years without stopping without experiencing any side effects, so there is good evidence that long-term exposure to the molecule is safe. But to see whether suppressing IgE could reduce the body's effectiveness in fighting off parasites, the researchers conducted an additional experiment on mice. They found that the vaccine did not dampen the immune response to infection. Strongyloides rattiparasitic nematode worm.

Koenig hopes that such a vaccine will be effective in people. “They know that the mouse created an antibody that correctly bound the human IgE molecule. If people create the same molecule, then I think there's a pretty good chance it will work quite well.”

However, clinical trials are needed to evaluate the vaccine's safety, effectiveness and duration of action in humans, Reber says. If it does come to market, he believes it could be a cost-effective way to treat people with severe allergies, as it would require far fewer injections than anti-IgE monoclonal antibodies such as omalizumab.