Mucosal tissue, which lines both the respiratory and digestive tracts, has long been known as an effective barrier against allergens. Recent research shows that Foxp3-directed regulatory T cells (Treg) are produced in the mucosal tissue and remain there to prevent allergic reactions. New ones are tailor-made every time an unknown protein is inhaled or ingested.

When people suffer from allergies, something goes wrong in the process by which Foxp3 signals Treg cell formation. The inability to make Treg cells therefore results in high susceptibility to becoming allergic.

This research represents an important step in understanding the genetic and cellular mechanisms underlying the allergic response, which may lead to more effective therapies. The findings are reported in the 18 July 2008 issue of the journal Immunity.