Peanut allergy vaccine rewrites the immune system

Peanut allergies could soon become a thing of the past, thanks to a breakthrough vaccine candidate developed by the University of South Australia’s (UniSA) Experimental Therapeutics Laboratory in partnership with biotechnology company Sementis.

Peanut allergies occur when the immune system mistakenly identifies peanuts as an allergen, signalling immune cells to release chemicals and resulting in adverse reactions that can range from mild hives, cramps, nausea and vomiting to life-threatening anaphylactic reactions. Severe allergic reactions can include impaired breathing, swelling in the throat, a sudden drop in blood pressure, dizziness and even death.

Peanuts are one of the most common food allergies, and the most likely food to cause anaphylaxis or death. In Australia there is particularly high prevalence of peanut allergies, with one in 200 adults and almost three in every 100 children affected.

“Parents are constantly protecting their child from being exposed to peanuts in all forms — from popular breakfast cereals and school snacks to biscuits, cakes and even health foods — whether at home, school or in social situations,” said UniSA’s Dr Preethi Eldi, who served as project lead on the new research. “And it means being vigilant and imposing very stringent dietary restrictions, not only for the child, but often also for family members.

“If we can deliver an effective peanut allergy vaccine, we’ll remove this stress, concern and constant monitoring, freeing the child and their family from the constraints and dangers of peanut allergy.”

The new peanut allergy vaccine is formulated by packaging bits of peanut proteins into the Sementis Copenhagen Vector (SCV) virus platform, developed by Sementis Chief Scientific Dr Paul Howley and UniSA Professor John Hayball, Head of the Experimental Therapeutics Laboratory. Prof Hayball said the virus platform rewrites the body’s natural response to peanut allergens, tricking the immune system so that the body responds normally instead of generating an allergic reaction.

“We’re effectively reprogramming the body to see peanuts as an entity that can be cured by a vaccine, rather than an allergen that elicits an allergic reaction,” he said.

“Already, the vaccine is showing signs of success, shifting peanut-specific immune responses in mouse models of peanut allergy and in preliminary in vitro vaccination-like studies using human blood samples from clinically confirmed peanut allergic people.”

Prof Hayball said the next steps are to gain further human samples and confirm the efficacy of the vaccine, which will demonstrate human translational capacity and increase the chances of success in future clinical trials. This efficacy evaluation will be made possible thanks to funding from the Channel 7 Children’s Research Foundation.

Dr William Smith, Head of the Clinical Immunology and Allergy unit at the Royal Adelaide Hospital and lead clinician involved in the study, said the development of immunomodulatory therapeutics has so far proved extremely challenging for scientists everywhere, with varying degrees of clinical desensitisation of peanut allergy but none that have succeeded in safely and completely eradicating peanut allergy.

“An effective vaccine for use in peanut allergy must be safe to administer with minimal adverse events, have a short immunisation schedule to improve compliance specifically with peanut allergic children and, most importantly, induce lifelong protection,” Dr Smith said.

“The preliminary data is encouraging and favours that the vaccine can meet all these criteria. It’s very exciting research and we are very positive to take the next step into what we hope will be a cure for peanut allergy.”

Image credit: ©iStockphoto.com/Sheryl Griffin

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