A new study published in Science by researchers from the Ragon Institute, NIH/NIAID, and the University of Chicago reveals a critical function of the immune system: how regulatory T cells (Tregs) selectively suppress autoimmune reactions while allowing protective responses against infections. The immune system must constantly balance two opposing forces—attacking harmful invaders while preventing damage to healthy tissues. When this balance fails, it can lead to autoimmune diseases, where the immune system mistakenly attacks the body.

In this study, researchers investigated how Treg cells prevent autoimmune reactions during infections. Using novel mouse models, combined with advanced tissue imaging and computational analysis, they found that Tregs specifically target immune cells that recognize self-proteins, preventing them from attacking the body while still allowing immune cells to fight infections. 

The study was a highly collaborative effort between the Wong Lab, the Savage Lab of UChicago, and the Germain Lab of the NIH. The experiments and analysis were co-led by Dave Klawon of the Savage Lab and Nicole Pagane of the Wong Lab, who are both co-first authors of the paper.

This discovery sheds light on why the immune system rarely triggers autoimmunity during infections and could lead to potential new approaches for treating autoimmune disorders, such as multiple sclerosis and lupus. By better understanding how Treg cells function, scientists could develop therapies that selectively regulate immune responses, helping to prevent harmful inflammation while preserving the body’s ability to fight disease.

This study represents a major step toward understanding the complex interactions between immune tolerance and immune defense. As scientists continue to explore the role of Treg cells in human health, these findings could pave the way for targeted therapies that better control immune responses in a variety of diseases.