Researchers have discovered that a single precursor cell can form both major cell types of the thymus. The finding, described in two papers in the 22 June 2006 issue of Nature (Vol. 441, No.7096; pp. 998-991; 992-996), helps resolve a long-standing controversy over the origins of thymus epithelial cells and may have implications for the treatment of thymic disorders.
The thymus is critical to immune system functioning because it provides an environment for T cells to develop and mature. The small organ is separated into two compartments, the cortex and medulla, each containing functionally distinct populations of epithelial cells that are important for successive stages of T-cell development. But the origin of these cells is a subject of debate.
Graham Anderson and colleagues now show that cortical and medullary epithelial cells are both derived from the same precursor cell in embryonic mice. Thomas Boehm and colleagues show that a similar cell is present in mice shortly after birth, and that the bipotent precursor cell can give rise to a complete and functional thymus.
The findings hint that, in the future, transplants of these thymic epithelial precursor cells might help restore impaired thymus function.
Graham Anderson (University of Birmingham, UK)
Thomas Boehm (Max-Planck Institute of Immunobiology, Freiburg, Germany)
Hans-Reimer Rodewald (University of Ulm, Germany)
(C) Nature press release.
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