Tracking Tregs

The paper:

J.D. Fontenot et al., "Regulatory T cell lineage specification by the forkhead transcription factor Foxp3," Immunity, 22:329-41, 2005. (Cited in 217 papers)

The finding:

Using a GFP-tagged knockin mouse, Alexander Rudensky's group at the University of Washington in Seattle showed that the expression of the transcription factor Foxp3 defines a subset of regulatory T cells involved in suppressing autoimmune activity.

The surprise:

Unlike most other transcription factors, which are expressed in multiple systems or tissues, Foxp3 was found only in a subset of αβ T cells. "It's a very rare instance when there is a dedicated function," Rudensky says. At the time, CD25 expression was the best available marker for identifying regulatory T cells; Foxp3's surprising specificity has since made it a more reliable marker.

The follow-up:

Rudensky and his colleagues found that Foxp3 expression not only defines regulatory T cells, but is also necessary for the...