Clostridiales or the Bacteroidetes bacterial species present in the human infant gut found to protect against food allergies, according to a new study led by investigators from Brigham and Women’s Hospital and Boston Children’s Hospital.
Recent insights about the microbiome the complex ecosystem of microorganisms that live in the gut and other body sites have suggested that an altered gut microbiome may play a pivotal role in the development of food allergies.
Every three minutes, a food-related allergic reaction sends someone to the emergency room in the U.S. Currently, the only way to prevent a reaction is for people with food allergies to completely avoid the food to which they are allergic. Researchers are actively seeking new treatments to prevent or reverse food allergies in patients.
In preclinical studies in a mouse model of food allergy, the team found that giving an enriched oral formulation of five or six species of bacteria found in the human gut protected against food allergies and reversed established disease by reinforcing tolerance of food allergens. The team’s results are published in Nature Medicine.
“This represents a sea change in our approach to therapeutics for food allergies,” said co-senior author Lynn Bry, MD, PhD, director of the Massachusetts Host-Microbiome Center at the Brigham. “We’ve identified the microbes that are associated with protection and ones that are associated with food allergies in patients. If we administer defined consortia representing the protective microbes as a therapeutic, not only can we prevent food allergies from happening, but we can reverse existing food allergies in preclinical models. With these microbes, we are resetting the immune system.”
The research team conducted studies in both humans and preclinical models to understand the key bacterial species involved in food allergies. The team repeatedly collected fecal samples every four to six months from 56 infants who developed food allergies, finding many differences when comparing their microbiota to 98 infants who did not develop food allergies.
Fecal microbiota samples from infants with or without food allergies were transplanted into mice who were sensitized to eggs. Mice who received microbiota from healthy controls were more protected against egg allergy than those who received microbiota from the infants with food allergies.
Using computational approaches, researchers analyzed differences in the microbes of children with food allergies compared to those without in order to identify microbes associated with protection or food allergies in patients. The team tested to see if orally administering protective microbes to mice could prevent the development of food allergies. They developed two consortia of bacteria that were protective.