This Could Completely Change How We Understand & Treat Food Allergies
Every time you sip your morning coffee or bite into a cookie, your body is quietly pulling off a biological miracle. Food is foreign material entering your system, yet your immune system knows not to attack it. Instead, your body recognizes the food as safe and lets it pass through the gut without incident.
This process is called oral tolerance, and it's something most of us take completely for granted. But for the 6% of young children and 3% to 4% of adults who experience food allergies, this system has gone awry. When someone has a food allergy, their body has decided that certain foods are threats, triggering reactions that can range from uncomfortable to life-threatening.
A new study published in Science Immunology has identified specific proteins1 that help the body decide what it will tolerate or reject—and it could change how we understand (and eventually treat) food allergies.
What we do & don't know about food allergies
Scientists have spent years identifying the proteins in common allergens, like peanut and egg, that trigger allergic reactions. When someone with an allergy encounters these foods, their antibodies recognize them as dangerous and activate the immune system's fast-acting inflammatory cells, resulting in symptoms ranging from hives and swelling to anaphylaxis.
Given existing knowledge about what causes allergic reactions, researchers sought to learn more about what causes the immune system to tolerate foods in this study.
They understood that specialized immune cells called regulatory T cells play a role in tolerance. These cells have anti-inflammatory, immune-suppressing properties that helps keep the peace when food enters the body. What remained a mystery was which specific proteins these regulatory T cells were responding to in food when they decided it was safe.
What the research says
Researchers screened mice eating a normal bowl of mouse chow to assess their levels of regulatory T cells on a normal diet, looking at what those cells were attaching to. Then they mapped backward to identify the specific protein segments—called epitopes—that the T cells recognized. The findings revealed three specific epitopes that signal "safe" to the immune system.
The three epitopes came from foods you likely eat regularly: corn, wheat, and soybean. Notably, all three are seed proteins—highly abundant plant proteins that appear to be easily recognized by the immune system's tolerance mechanisms.
Corn epitopes had the most abundant T cell response, which makes sense because corn allergies are relatively rare. The immune system seems well-equipped to tolerate it.
Scientists were particularly excited about the discovery of the soybean epitope, because soy is one of the major allergens in humans. Understanding what tolerance to soy looks like at the protein level could be key to developing treatments. Interestingly, the researchers found that the receptor interacting with the soybean epitope interacts with sesame as well. This could help explain "cross-tolerance," or how tolerance to one food confers tolerance to another.
Where these immune cells live & how they work
The study also explored where these tolerance-promoting regulatory T cells hang out. Researchers primarily found them in the gut, which makes sense given that's where food meets the immune system.
What's more, the researchers found that these cells behave differently depending on their environment. In a healthy gut, they work to maintain an absence of inflammation. In an inflamed environment, they actively work to reduce that inflammation.
What this means for the future of food allergy treatment
This is foundational research conducted in mice, meaning it's not a cure that's ready for human use. But it does point toward promising possibilities.
Scientists have already been exploring regulatory T cells as a potential immunotherapy route for people with severe food allergies. The idea is to one day create regulatory T cells that are pre-programmed to tolerate certain foods and dampen immune responses to common allergens.
In the nearer term, the researchers are excited to adapt their protein-mapping workflow for human studies.
The takeaway
So, for the millions of people managing food allergies, this won't change anything tomorrow. But it's a meaningful step toward understanding why some bodies tolerate certain foods while others don't, and this understanding will likely be the foundation for better treatments down the road.