A decade ago, a landmark clinical trial in the U.K. revealed that introducing peanuts to infants early in life significantly reduced the risk of developing peanut allergies. Now, researchers at Memorial Sloan Kettering Cancer Center (MSK) believe they’ve uncovered the biological reason behind this phenomenon: a newly discovered immune cell called the Thetis cell.
First described by MSK scientists in 2022, Thetis cells are a unique type of antigen-presenting immune cell. Their role is to educate the immune system, helping it decide when to attack harmful invaders and when to tolerate harmless substances—like food proteins. This new study, published in Science, shows that Thetis cells play an essential part in preventing allergic reactions to foods by promoting what’s known as “oral tolerance.”
Using genetically engineered mouse models, the researchers found that Thetis cells are most abundant during a crucial early-life period. During this “developmental wave,” Thetis cells in the gut help train regulatory T cells to suppress immune responses against common food allergens, such as egg proteins. This early exposure helps the immune system learn to tolerate these proteins instead of reacting aggressively.
“The number of regulatory T cells generated during this developmental wave in young mice was about eight times higher than in adults,” explained co-first author Yollanda Franco Parisotto, Ph.D. “And once this tolerance is established, it lasts a lifetime.”
This finding supports why early introduction of allergens like peanuts can be protective. Introducing allergens later in life doesn’t produce the same strong tolerance, because fewer Thetis cells are present to ‘put the brakes’ on the immune system’s inflammatory responses.
Senior author Dr. Chrysothemis Brown highlighted the potential for new therapies. “We’ve shown there’s a window where stronger tolerance is generated, mediated by Thetis cells. This suggests we might one day deliver food antigens directly to Thetis cells to promote tolerance, even after this early window closes.”
Though the study was conducted in mice, Thetis cells have been found to be very similar in humans. This discovery also explains why allergies develop differently depending on how allergens are introduced — for example, exposure through the skin can trigger allergies, while early oral exposure fosters tolerance.
The research team, including pediatric hematologist-oncologist Vanja Cabric, MD, and immunologist Alexander Rudensky, Ph.D., is also exploring how Thetis cells influence immune responses to early childhood cancers, opening new frontiers for understanding immunity in young children.
You Might Be Interested In:
- What Is the Allergy Medicine for Cedar Fever?
- What Is the 5 Best Allergy Medicine for Puffy Eyes?
- What to Expect with Allergy Shots?
