Blocking Immune Signal Two Expands Gut Tolerance Cells, Opening New Paths for IBD Treatments

Weill Cornell Medicine investigators have made an unexpected discovery about how the immune system normally suppresses inappropriate chronic inflammation in the intestine, potentially opening new avenues for therapies against inflammatory bowel disease (IBD), food allergy and other autoimmune conditions.

The study, published April 24 in the Journal of Experimental Medicine, focused on the cell-to-cell signals required for the immune system to tolerate commensal gut microbes as well as foreign proteins from food. The researchers examined a signal that had been considered necessary for expanding the population of tolerance-enforcing immune cells. They found unexpectedly that only blocking this signal was effective for driving tolerance in intestine through a specific cell subset—and powerfully suppressed gut inflammation in a preclinical model.

“We think this is a paradigm-shifting discovery that will lead to new treatment approaches for chronic inflammatory disorders of the intestine,” said study senior author Dr. Gregory Sonnenberg, the Henry R. Erle, M.D.-Roberts Family Professor of Medicine and associate vice chair of research in medicine, and faculty member of the Division of Gastroenterology & Hepatology and the Jill Roberts Institute for Research in Inflammatory Bowel Disease at Weill Cornell Medicine.

The study’s lead and co-corresponding author is Dr. Mengze Lyu. The research was conducted by investigators from Weill Cornell Medicine and published in the Journal of Experimental Medicine on April 24, 2026.

Understanding Immune Tolerance in the Gut

The immune system must distinguish between harmful pathogens and beneficial or harmless substances such as gut bacteria and food proteins. When this balance is disrupted, it can lead to chronic inflammatory conditions like IBD. The Weill Cornell team investigated a specific intercellular signal previously thought to be essential for promoting the expansion of immune cells that enforce tolerance in the intestine.

Contrary to expectations, blocking this signal—not enhancing it—proved effective in driving tolerance through a distinct subset of antigen-presenting cells characterized by the expression of RORγt. These RORγt+ APCs were found to play a critical role in establishing immune tolerance in the intestinal environment when the signal was inhibited.

Preclinical Results and Therapeutic Implications

In preclinical models, inhibiting the identified signal led to a powerful suppression of gut inflammation. This outcome suggests that targeting this pathway could offer a new therapeutic strategy for IBD and related disorders where current treatments may lose effectiveness or carry significant side effects.

The researchers emphasize that their findings reveal a previously unrecognized mechanism by which the immune system maintains homeostasis in the gut. By modulating this specific cell-to-cell interaction, it may be possible to restore tolerance without broadly suppressing immune function.

Context in IBD Research

Inflammatory bowel disease, which includes Crohn’s disease and ulcerative colitis, affects millions worldwide and involves an abnormal immune response to the gut microbiota. While biologic therapies targeting specific immune pathways have transformed treatment for many patients, a significant portion either do not respond adequately or lose response over time.

Emerging research continues to explore ways to promote immune tolerance rather than simply inhibit inflammation. Approaches aimed at expanding regulatory T cells or modifying antigen-presenting cell function represent active areas of investigation. The Weill Cornell finding adds a novel dimension to this effort by identifying a counterintuitive role for a signal once thought to be purely stimulatory in tolerance development.

Next Steps and Considerations

The study was conducted in preclinical models, and further research will be needed to determine whether the same mechanism operates in humans and whether it can be safely translated into clinical therapies. The investigators note that understanding the precise conditions under which blocking this signal promotes tolerance—without risking unintended immune effects—will be critical for future development.

No clinical trials based on this specific approach are currently mentioned in the available sources. As with all early-stage discoveries, the timeline for potential human application remains uncertain and will depend on subsequent validation studies.