Murine CD4+ T cells from DEREG mice expressing GFP under the control of the FoxP3 promotor

Naturally occurring CD25+CD4+ regulatory T cells (T reg cells) are currently intensively characterized because of their major importance in modulating host responses to tumors and infections, in preventing transplant rejection, and in inhibiting the development of autoimmunity and allergy. Originally, CD4+ T reg cells were identified exclusively by the constitutive expression of CD25, and many in vivo experiments have been performed using depleting antibodies directed against CD25. However, both the existence of CD25 T reg cells, especially within peripheral tissues, as well as the expression of CD25 on activated conventional T cells, which precludes discrimination between T reg cells and activated conventional T cells, limits the interpretation of data obtained by the use of anti-CD25 depleting antibodies. The most specific T reg cell marker currently known is the forkhead box transcription factor Foxp3, which has been shown to be expressed specifically in mouse CD4+ T reg cells and acts as a master switch in the regulation of their development and function. To address the question of the in vivo role of T reg cells in immunopathology, we have generated bacterial artificial chromosome (BAC)transgenic mice termed depletion of regulatory T cell (DEREG) mice, which express a diphtheria toxin receptor (DTR) enhanced GFP (eGFP) fusion protein under the control of the foxp3 locus, allowing both detection and inducible depletion of Foxp3+ T reg cells. The gene expression profile of both CD4+eGFP+FoxP3+ and CD4+eGFPnegFoxP3neg cells isolated from DEREG mice was here analyzed by micro array.

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Anz D, Koelzer VH, Moder S, Thaler R, Schwerd T, Lahl K, Sparwasser T, Besch R, Poeck H, Hornung V, Hartmann G, Rothenfusser S, Bourquin C, Endres S