Autoimmune pathology often occurs because some immune cells are not regulated properly. This important function is usually the responsibility of a special class of cells called regulatory T cells (Treg cells). A pair of new reports in the November issue of Nature Immunology show that Treg cells require the immune modulator interleukin 2 (IL-2) for their maintenance and long-term function rather than for development, as previously thought.
How Treg cells develop has been worked out in some detail and the prevailing model included a fundamental function for IL-2. In fact, for many years, Treg cells were identified exclusively on the basis of expression of the IL-2 receptor. But the new studies by Alexander Rudensky and Ludger Klein rely instead on identifying Treg cells by a different molecule, Foxp3.
Using this identifier, both Rudensky and Klein unexpectedly demonstrate that IL-2 signals are not required for Treg cell development. Instead, IL-2 is required for the maintenance of Treg cells after they leave the thymus and move into the circulation. This new model for the function of IL-2 will help scientists understand how this critically important class of suppressor cells keeps immunopathology at bay.
Alexander Rudensky (University of Washington, Seattle, WA, USA)
Ludger Klein (Research Institute Of Molecular Pathology, Vienna, Austria)
Additional contact for comments on paper:
Fiona Powrie (Oxford University, UK)
Abstracts available online: Paper 1, and Paper 2.
(C) Nature Immunology press release.
Message posted by: Trevor M. D'Souza